DIALOGVE 1. The definition of Clocks: the reason of their Several distinctions, with an account of the most common kinds now in use.

BEing desirous to furnish my self with sufficient knowledg in things of either use or pro­fit to man, I considered the sa­fest Inquiry would be of per­sons whose knowledge was compleat in those things which I purposed to inquire af­ter, to which end, being desirous, among o­ther things, to understand as much of the nature, use, and right managing of Clocks as was possible for one that was not a work­man, [Page 2] in that kind, I thought it best to ap­ply my self to you; who, being an able Ar­tist in that profession, may therefore be the more likely to satisfie my curiosity in this particular, provided you are as willing, as God and education hath made you able.

Sir, the most noble and ingeni­ous productions of Nature and Art (I have observed) are alwaies of more value and esteem among men, when their vertues and qualities are throughly understood and truly discovered, then they are so long as the same lyeth hidden and concealed; which Consideration is to me a suffici­ent motive to ingage my self to serve you in this your request as far as my weak capacity will permit me, especially in those things that are absolutely necessary to be known by those that intend to make use of any sort of Clocks whatsoever, hoping thereby to whet the edge of your esteem of so ingenious an art. Propound therefore those things you would be satisfied in and I shall indeavour to give you an answer.

In the first place let me under­stand [Page 3] what you define a Clock to be.

A Clock is a certain instrument in­vented and contrived, to give the true hour, either of the day or night, (by the Circuler moving or certain wheels and pinions artificially disposed within the Bo­dy of the Instrument) without the help of either Sun, Moon, or Stars, or any other of those elemental assistances, which the Antients did in former ages make use of to divide their time by.

Are Clocks more useful for find­ing the hour, then any other Instrument heretofore made use of.

Clocks in that perfection, in which this age enjoys them, excel all other in­struments in its officiousness at all times, and in all places, as well in the nights, as in the day, as well in cloudy skies as in clear weather, as well in close roomes as in the open Air, which no other Ho­rological Instrument besides this is able to perform, many being defective, where the Sun giveth a perpendicular shaddow, and in cloudy weather, in close roomes, and in the night, most are likewise of no [Page 4] use; whereas on the contrary, let the time be when it will, the weather what it will, or the place where it will, all is one to a Clock, it shall give the time as certain in one as in another, provided it be in perfect order, and well adjust­ed.

From whence are all those vari­ous names, and denominations of Clocks derived.

They are derived, first, from that which is the principal and prime cause of their motion, being either weight or Spring.

Secondly, from that, which retards and regulates the violent motion of the wheels, being either, ballance or pen­dulum.

Thirdly, from the time they continue in motion at once winding up, some going 16 houres, some 30 hours, some 8 days, some 5 weeks, some 3 moneths, some 6 moneths, and some a year.

Fourthly, from the offices which they perform, some giving the hour onely by the pointing of the needle, others express [Page 5] the same by the sound of a bell. Some strike quarters, some repeat the hour, and some chime tunes.

So that from the permiscuous intermix­tures, of these four foregoing heads, are derived all these various and manifold distinctions, and denominations, under which they have been exhibited unto the world, of which be pleased in the fol­lowing Scheam to take a view of.

[Page 7]To all which, if you adde that space of time, they continue in motion at once winding up, you have the names of 40. Of the chief and most common kinds now in use among us, the reason why I have omited the mentioning of some which have been formerly, and are still made use of, which differ from these aforementioned both in name and na­ture, is, because they are but the produ­ctions of meet whimseys, not at all answering the expectations of those that composed them, or have made use of them, upon which account tis Judg­ed, their memory may perish with their dissolution, for want of the same kind to succeed them, when they are decay­ed, and therefore since there is uo likelyhood, of their being much or long in use, I have forborn to speak any thing of them.

DIALOGVE II. The manner how all Clocks natu­rally perform their Offices.

BY what you have delivered in the foregoing discourse, among other particulars therein mentioned, I find that Clocks perform their offices by wheel-work, but in what manner they move, or act, I am still ignorant, and therefore would be gladly informed somewhat thereof.

All Clocks, consist of one or more parts, or sets of wheels and pi­nions, (a set consisting commonly, of so many wheels and pinions, as are mo­ved by the draught, or poysute, of one Weight or Spring.) Of those that con­sist but of one part, or set of wheels, are pocket Watches, and all other mo­ments of what form or fashion soever, that strike not on a Bell; these having [Page 9] their Wheels and pinions differently indented in their perypheris (according to the judgment of him that composeth it.) do by vertue received from either Weights or Springs, successively move each other in a circular manner, having the rapidity of their motion, so retard­ed and regulated, by either Ballance or Pendulum, that the needle, who also is moved with the rest of the work performs its revolution in twelve hours (or parts of time) thereby dividing at twice going round, the day and night into twenty four equal parts, which are commonly expressed by the pointing of the needle to a Circle equally divided into twelve parts, which are called hours, whereunto are annexed figures, sufficient to distin­guish the successive divisions thereof, so that by the pointing of the needle, to a­ny of those divisions, or their inter­mediate parts, you have the true hour given, whensoever you make inspecti­on thereon.

Those that consist of more sets of Wheels then one, are all those move­ments [Page 10] that strike on bells, of which the Clock is one, being composed of two parts, a watch part, and a striking part, the watch being the same as was spoken of before, I shall pass here: as for the strikeing part, it is that where­by the Clock is made by art to give intelligence of its divisions of time, by strikeing several successive blows on a bell, sufficient to express the number of hours, that have passed, since the last meridian altitude, or depression of the Sun, which is thus performed.

The wheels contained in the striking part being at the end of every hour un­locked by certain detents for that pur­pose appointed, continue the rapidity of their motion which is the cause of the hammers striking until the locking de­tent, which is appointed to stop them, fall into the next successive notch of a moving wheel, called the count wheel, for that purpose indented concentrick at severall distances according to the number of strokes at each time to be strucken.

By the description here given I [Page 11] am much satisfied, concerning the natu­ral motion of wheels in a Clock, but if you have any thing further to declare I shall be very desirous to hear it.

There is nothing more to be spoken concerning this matter that will be worthy your attention; what hath al­ready been delivered is sufficient, for there in not any part of Clock work whatsoever which moveth not accord­ing to the order here before described, so that if they contain quarter repeating or Chime parts, yet their order in motion is the same in effect with what hath been before delivered.

DIALOGVE III. Wherein the goodness and excellency of a Clock chiefly consisteth.

That little knowledg which I have gained by our former discour­ses makes me, still the more desirous to be informed further concerning these [Page 12] motions of returns, whereof in the next place I shall desire some account where­in the chief goodness of a Clock con­sists that I may (at least in discourse) be able to difference those that are good from them that are bad.

The chief goodness of a Clock consists chiefly in these two things; first in its dureableness; secondly in its officious­ness; and that it may be either durable or officious several things are requir­ed.

First for its durableness the first thing required is that the chief parts of which it is composed, be of metal answer­able in hardness to the extremity of its performance.

And Secondly that true proportion and uniforme figure be observed in all its parts.

You speak well in my opinion as to the first of these, for I am certainly perswaded that those german movements and others, formerly made, were far more lasting and dureable then those which these latter ages have produced for cer­tainly, [Page 13] them whose wheels and other parts were made of the purest steel must needs outlast those who are made in brass, it being a much softer metal and so consequently more subject to de­cay.

Your not right understanding the first thing required in my first pro­postion hath been the cause of this your great mistake. I confess indeed that some part of those antient movements you speak of do in our days seem many of them to be very little worn: Yet I will prove to you by plain and evident reasons, that those Clocks and Watches, which we make now a dayes (though the wheels and other parts are composed of brass the softer metal) shall in the general out last all others whatsoever, provided it be truly and religiously wrought: to prove which consider first that the service of all pinions are in such proportion to the wheels that moveth them (or are moved by them) as their numbers are one to another so that if a wheel contain sixty teeth and the [Page 14] pinion which it moveth about contain but six, the service of this pinion must needs be ten times as much as the ser­vice of that wheel, because it maketh ten revolutions to the wheeles one, and so by consequence every tooth (or leaf) of that pinion must be worn ten times as much as every tooth in that wheel, to make therefore these wheels and pi­nions to wear a like, and continue the one as long as the other, tis requisite that the substance of the pinion should be so many degrees more hard and du­rable (as its proportion of wearing is) then the substance of the wheel which moveth it, by which means they will wear better and continue longer with­out reparation then otherwise tis pos­sible for them to do; for if you observe those german movements you speak of (whose wheels and pinions and other parts are all of steel) you shall find the pinions irrepairably decaied, when the wheels are never the worse, for since that almost all the wearing to which those parts are liable be laid one the pi­nions, [Page 15] we may reasonably conclude that they are sooner worn out (by just halfe the time) then they otherwise would have been, if the wheel had been made of such a metal, whose proportion of hardness or softness would have admit­ted an equal share of wearing with it, which ill conveniencies are all avoyded by that method of working now a days us­ed in framing of these movements: there fore in this sort of work take this for a general rule (where there is no excepti­on) that what proportion of wearing one part beareth unto another such a pro­portion of hardness should the metal of the one have above the other to make them wear equal, and Continue long in that placide estate of motion which is requisite in things of this nature.

I am now in part convinced of my error, but yet, I think, your general rule holds not good in all parts of a Clock, for then how comes it to pass that in Clocks, you make their pevets which are of steel, to move in frames of brass this according to your general rule can­not [Page 16] wear equally, because they are sub­stances of unequal hardness, yet perform both the same taske; whence we may conclude that the more soft must needs be more sensiable of the wearing then that which is more hard, therfore how can your method of working, be good in these parts.

The rule and method holds good still (with our exception) for though it be an ill convenience in other parts, yet in pevets and their receptacles it is not so, for reason requires if 'twear possible, that all the wearing to which those parts are subject should be in the pevet holes, and not in the pevets themselves; for when pevets, are worn and decayed theres no repairing them without new pinions (which is exceeding chargeable) whereas pevet-holes are more easily reduced and with far smal­ler cost, thus of two evils we have cho­sen the least.

Why are true proportion and uni­form figure required to make the move­ment of a Clock more lasting and dur­able.

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True proportion and uniform fi­gure are required, because without it, movements of this Nature cannot per­form, and we count a Clock to be worn or (which is all one) to be of no value, when he ceaseth to perform that office for which he is designed: if therefore the teeth of the pinions are not proportional to the teeth of the wheels, or the teeth of both to themselves, if the pevets are too big or too little, if the wheels are too large, or the generality of the work too heavy and cumbersom, 'tis certain this Clock is not of the number of those that are ac­counted the best.

What is required in its officious­ness to make it good or excellent?

In its officiousness two things are required, first continuance in motion; secondly regularity in the same: as to the first of these 'tis certain, that those Clocks, that have true proportion in their parts and uniformity of figure also, must needs [...] a Clock of continuance in motion, according to the best kind? pro­vided it be well defended, by case or o­therwise, [Page 18] from air and dust; the one be­ing subject to rust the steel work, which may happen to put a stop to its motion, and the other, by clogging the teeth, and choaking the pevets, will be apt to produce the same effect.

As to their regularity I shall say only thus much, that those Clocks, who have their motion regulated by a Pendu­lum, are more excellent then those who are regulated by a Ballance, and those, that are regulated by a long Pendulum, are far more excellent than those that are regulated by a short one; to all which I shall add this one general rule, that those Clocks are to be ac­counted best, that perform most with least work.

DIALOGUE IV. Of the several conclusions that have been, are, and may be wrought by the motion of Clockwork.

Is it possible by the moving of Clockwork to represent or work any other motion or conclusion then that of the hour.

Of those several motions and conclusions that may be wrought by Clock-work I will give you an account as far as my knowledge or in­quiry will permit me: the first thing I shall deliver as possible to be effected by their motion, is that first they may be made to show the month of the year, the days of the moneth, the the hours of the day, the minutes of an hour, and the secants of a mi­nute.

2, They may (besides the hour [Page 20] in any particuler place) be made to shew the hour in any place of the known World; so that, by inspe­ction thereon, you may have readily given you the hour at that time, as it is naturally, in any particuler known Region, Kingdome, or Prin­cipal City in the Universe.

3. They may be made to shew the Suns place in the twelve signs of the Zodiack, his declination from the equi­noctial, his right and oblick ascention, his amplitude, rising and setting, length of the day and night, with the beginning and ending of twilight, throughout the whole year.

4. They may shew the moons age, time of her new, full, and quarters, her rising, and setting, and southing, her time of shining, and motion through the twelve signs of the Zo­diack.

5. They may shew the rising, setting, and southing of any fixed Stars.

6. They may shew the time of the [Page 21] tide or full sea in any Port or Harbour whatsoever.

7. Besides the hour, they have been made to strike the minutes, and quarters, repeat the hour, Chime Tunes on Bells, play on the Organ, Harpsecal, or Virginal.

8. Besides the lively and delight­ful motion that hath thereby been giv­en to Artificial Creatures, such as dogs, mice, flyes, fouls of the air, and figures of men, women, and the like.

Besides all which it hath been re­ported, by one of the Ancients, that a Prince in his time was (by a German) presented with a Clock, which, besides the hower, did also represent the mov­ing of the seven planets in their direct retrograde and stationary motions: which if true was a work worthy ad­miration.

DIALOGVE V. Some few rules how a man may furnish himself with either Clocks or Watches that are really good and substantial.

The time that hath been spent in giving and receiving these first Rudiments of knowledge in this kind, hath in my opinion been som­thing larger then necessity seems to require, Considering that what hath been delivered has rather been to sa­tisfie an inquisitive curiosity then for any great use or profit contained therein; therefore since I have gained sufficient knowledge in these lesser mat­ters let us proceed to those of more importance, and herein I shall desire you to give some few directions what course is safest to be taken in furnish­ing my self with a good Clock.

If you intend to furnish your self with Clocks that are really good [Page 23] and substantial you must observe these three rules.

First that you apply your self to a work-man who is of reputed ability: he that is master of his Art is the only person in nature from whom you can in reason expect either Clocks or a­ny other movements whatsoever that are perfect, sound, and good work.

You say well, but I have ob­served, that same or repute is many times the product of some particular affections, and too often is conferred one those that least deserve it, there­fore that I may not be deceived in the repute of a work-mans ability what rule shall I walk by.

Not by the populer applause of light and vain petsons: but by the commendation of the more sober and soled sort of men.

Not by the fame of unexperienced relations; as by the testimony of his own labours.

Not by his fair and beautiful ex­pressions [Page 24] but by his plain down­right and solid reasons.

So that if his reputation be derived from gravity: if his work have per­formed according to the expectaion of those that have used it: and he be able to give a reason of any thing that falls in his business, you may in a large manner put confidence in his abi­lity.

But some Clocks that have been made by persons of good repute have failed exceedingly in their per­formance (as might be instanced in several) though they indeed at last were perfected, but it was with a great deal of trouble.

This might be for several other reasons, and not from any deficience in the work-man; as first, it might be some accidental injury in the convei­ance from one place to another, as sometimes happens by jogs or Squats which loosen either pins, wedges or screws which many waies may impede its motion.

[Page 25]Secondly there may be some small matter not freed in the finishing, which many times escapes the care of the best work-man, and may happen not to dis­cover it self till sold, all which may occasion some defect in its perform­ance, and this defect may occasion some trouble to find its cause, for if the cause be once found tis then ea­sily cured, only the hardest thing is to find the cause, but however the work of a reputed Artist, may thus fail by chance, yet this can be no cause for you to distrust his ability, for the best work-man being but a man may be subject to error, and if in the general he prove a sound work-man once failing is not to be taken no­tice of.

What is the second rule I am to take notice of.

My second rule is that your work-man be not onely a person of reputed ability, but also of known in­tegrity, for though a found work-man be able to furnish you with good [Page 26] work; yet the safest dealing will be with him that is both able and honest, an able work-man can furnish you with good work, if he will, and an hon­est man will furnish you with good work, therefore he that is both able and honest, both can and will furnish you with good work if you observe.

My third rule, that you resolve to give a price valuable to the work you purchase, there is a saying which a­mong Clock-makers is aparently true, that he that sels a Clock for a small price cheats either himself or his cu­stomer, for if he sels good work at a low rate, he cheats himself; but if he sels bad work at a low value then he cheats his Customer, who expects (commonly) that it should be good though he buy it at an inconsiderable price; therefore if you are minded to furnish your self with a good Clock be as willing to give a good price as you are to have good work.

But suppose that I should ap­ply my self to such a person you speak [Page 27] of that is both of repute, ability, and known integrity, and one that for a good price hath made good work; yet, I fear, I may here be cheated, for when I come into his shop with a re­solution to give a good price for that which is good; I may have chance to pitch upon one that is not of his own make, for I have observed that they all keep servants, who seldome prove so careful as they ought, especially if their masters eye is not alwaies one them.

He that is honest and faithful in his dealing will certainly inform you of the difference if he finds you thus resolved valuably to purchase the best, but however considering temptati­ons your best way not to be deceived is to be speak it a fore hand agreeing with the work-man both for price, time of going, performance, and shape; this is the surest way, for a work man that knoweth his price knows also what time he can afford to spend in makeing it good.

But is it not possible for a man [Page 28] that is not an Artist, to be capable of knowing good work.

Tis very hard, yet to satisfie your desire I will give you two or three rules that may possibly stand you in some stead.

First be satisfied if possibly, whether the teeth of the wheels be cut down by an ingine or not, for there is no man can cut them down by hand so true and equal as an ingine doth,

Secondly let the vibrative traine of the Pendulum or Ballance be brisk and lively, continuing its motion some time after the tooth hath ingaged with its pallets, and not check or re­turn so soon as they have beaten thereon, tis alwaies commendable to to see Clock or Watch-work, move thus brisk and lively, and a great sign it hath passed a good hand.

Thirdly, Observe whether every particular part of it be true and square whether it be clean, smooth, and well polished, whether the needle or hand be true siled, and of a neat order whe­ther [Page 29] the hammer strike one the Bell so true as may cause it to give its sound clear and ful without intermixture of harshness and Jurgelling, and whether the work be generally in all its acti­ons lively, brisk and pleasant, if you find all these in a Clock you may con­clude it was made by the hand of a good work-man, and consequently that it is good work, which is alwaies best cheap though it cost dear.

DIALOGVE VI. The way and manner of packing up and conveying all manner of Clocks from one place to another, as occasion shall re­quire, as also rules to be observed in setting them up and fixing them in the places they are designed to stand in.

In removing of Clocks, as occasion may happen, how shall I do it without prejudice.

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If you have occasion to con­vey any Clock of worth from one place to another you must do thus: provide for it a coffin or box of deal boards or other wood, let it be strong enough, provided it be not too heavy and cum­bersome, let this box be of bigness sufficient to contain your Clock (with case or without) having besides space enough left both at bottom, top, and sides, to thrust in Straw, or Hay, (or any other matter that is soft and yeild­ing) in such quantity as may be suffici­ent to keep it free from the sides of the coffin: when you have thus pro­vided your coffin or box let your Clock (whether in case or otherwise) be carefully wraped up in paper or Cloths (according to its bigness) to keep it from dust and fowlness having before fastened every thing in it that may receive prejudice by being loose as the pendent of a Clock, or a Clock in the case, or the like: when you have thus wraped it up safe, then in the bottom of the coffin or box, place a [Page 31] lay of Straw, upon which lay in your Clock, then with Straw or Hay let it be so close packed up both at bottom, top, and sides, as the Clock may not-be able to stir therein (alwaies observeing to be careful of glases or ornaments that they be free from compressi­on) then fasten on the cover by nail­ing or Cording it; so is your Clock sufficiently packed up, and may he safely conveyed to any place whatso­ever without harm or prejudice.

When I have thus safely con­veyed it to any place, how then shall I deal with it to set it up rightly.

When you have gotten it home, the first thing you have to do is gently to open the box, pull out the packing and take out the Clock then take off that with which it is covered, loosen those things that are fastened in it, so is it ready to set up for going.

If it be a Ballance Clock of the ordi­nary sort, the trouble is not much but onely to drive in an hook into either [Page 32] post or brickwork, so that it may be fast, indriving of which observe not to drive it too far at first, till you have tried with your Clock whether it hang up right from the wall, if it be not e­nough you may drive it further till you find it enough, then hang thereon your Clock (by that provision which is made in it) as upright as your eye can Judge it will do well enough for these sorts; when you have hung it up, then hang on the weights, where note that they are, commonly marked, (or should be) the one with a W., the other with an S. let that weight that is marked with the S. be hung o [...] that line which is next the wall, and let that which is mark­ed with the W. be hung on the out most line, sometimes there are quar­ter Clocks which have more weights then two; in this case, it is convenient to fasten to the lines pieces of paper marked with the same marke that the weight is to be hung on it.

In what manner shall I set up a pendulum Clock.

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If your pendulum Clock be of the ordinary sort the trouble and manner of hanging it up is the same with the Ballance Clock, viz. to drive an hook for it to hang on, which when you have done you may hang on the weight without any difficulty, because they commonly go but with one, which you cannot well miss in hang­ing; the greatest difficulty is to hang those Clocks upright, for if they are not placed exact, they will not go, the onely rule to know when a Pen­dulum Clock hangs exactly is by the beating of the pendulum, for if it strike not equal, that is, if there be longer time between beating of one blow, then there is between the beating of another, be sure it stands not upright; to remedy which you must elevate either one side of the Clock or the other, till you find it to vibrate equal­ly, in doing of which observe, that if, when you have elevated one side of your Clock, it beats more unequal than before, then be sure you have e­levated [Page 34] the wrong [...] side, therefore pro­ceed to the elevation of the other, till you find it to vibrate equally.

What rules must be observ­ed in setting up the long-swing week­ly Pendulums, or others of the like na­ture.

In setting up long-swing Pen­dulums, after you have taken them from the coffin, open it, and make free all things that are fastened, as before was taught, then in the room it is designed to stand in, seek for some post if possible near the place you desire it should stand at, to which proster the Clock and case toge­ther as it is, which done fasten the back part of the Case with a nail or screw to the post, then hang on the weight according to the marks by the work-man given, and set the Pen­dulum on vibrating, and according to the beating of it you will understand which way to elevate or depress the same to make it beat equal and swing clear of the case: then when you have [Page 35] found it to stand in its true position, fasten it with another nail or two, that it may stand firm and not shake: the same rule that is given for this serves for all other trunck-cases whatsoe­ver.

What rules have you for pla­cing Spring (or table Clock.)

The difficulty of placing these is not great, for after you have loosed whatsoever was fastened for conveni­ency of carriage, you have no more to do but to set it on a Table, Cabinet, or other place convenient for it to stand on (which most commonly stand up right) but after you have placed your Clock thereon, if it be a pendulum and you find it not to beat right, you may remedy it by putting under that part of the Table, Cabinet, &c. that is too low, a smal wedg, till you find it to stand right and vibrate equal.

DIALOGVE I. Of pocket Watches; Watch and Larrums; and Clocks; their use right manag­ing and true adjusting.

What is the chief use of watches, watch and lar­rums, and Clocks.

The chief use of the pocket watch is, with the pointing of the needle to the circle of hours, to give the true hour of the day or night; the watch and Larrum not only giveth the hour by the point­ing of the needle, but is also by Art contrived to ring on a bell, at any cer­tain hour you shall appoint, being chief­ly [Page 38] designed to awaken people at any certain hour of the night, according as they shall have occasion to raise themselves; the Clock not onely giveth the hour by the direction of the hand to the Dial figures, but doth also (as I have said before) give intelligence of its divisions of time, by the sound of a Bell, strikeing thereon so many stroaks as are sufficient to give an account of the hour it expresseth.

What is to be learnt as ne­cessary to the right managing of these movements.

In the managing of the pocket watch, you must first wind it up right­ly; which you must do by turning the Key of it contrary to the moti­on of the Sun, or from your right hand upwards (or from you) to­wards your self, which ought also to be done not too hastily, least you force the stop, and break the string; and commonly those, that strive to wind them up the contrary way, bow ei­ther the teeth, or break the pinions; [Page 39] like unto this is the manner of winding up either Watch and Larrum, or Clock; but the Watch and Larrum, being ap­pointed to ring at any certain hour must thus be set to perform its task; they have commonly two circles wher­on, are ingraven the twelve hours, one in large or capital figures, the other in small figures, which are ap­pointed to set the Larrum by, within which is a small hand; now, what hour soever you would have your Lar­rums to ring at, to that figure, i [...] the in­nermost circle, set your Larrum hand; as if you would have it ring at five in the Morning, then set the little hand within the small circle (which I call the Larrum hand) to the figure of five contained in that small circle; then winde up the Larrum, and the next morning you willl see the effects.

How is the Clock to be or­dered.

The Clock, in the winding up of its several parts, must be order­ed as the watch, but in other respects [Page 40] requireth a different ordering, for if the hand be not at the true hour, it must be set thereunto gradually from one hour to an other, letting the Clock strike out betwixt each hour, for if you should turn the hand forward hastily two or three figures together, you will indanger the breaking of the detents, if they should happen to rise a­gainst the warning pin.

If the hand and the striking are not together, that is, if it strikes more or less then the figure, which the hand points at, you must bring them toge­ther thus, by lifting up continually the locking detent, so often as occasion serves, till by striking of it round you bring it to strike so many as the fi­gure signifies, to which the needle points.

How are these movements to be adjusted and brought truly to the hour.

In adjusting of these movements what is necessary in one, is sufficient for all, being all rectified in their go­ing [Page 41] by the same rule, if therefore a Watch go too fast, the spring must be let down to make it go slower, if it go too slow the spring must be taken up to make it go faster.

How shall this be performed.

By turning the endless screw, that the figures moved by it may in­crease or diminish: as if you would make it go faster, turn it that the fi­gures may pass from 1 to 2 and from 2 to 3 &c. but if you would have it go slower turn them from 4 to 3 and from 3 to 2 &c. and thus you may bring the most common pocket work to the true time or motion in which it should move.

It hath been observed, that some Watches go too slow when they are first wound up, and too fast when they are almost down, and some go too fast, when they are first wound up, and too slow when they are almost down; which all the leting down or taking up of the Spring would not remedy.

[Page 42]

This proceeds from a fuzey not truly adjusted to the draught of the Spring, and must be rectified by a work-man, being one of the hardest knacks that belong to a Watch-maker to perform exactly.

DIALOGUE II. Of ordinary domestick Ballance Watches, Watch and Larrums, and Clocks, their use, right manageing, and true adjust­ing.

what is the chief use of these movements.

The use of these is the same with those in the former discourse, (onely their use is more manual then these, and the use of these more dome­stick then they) but their manner of ordering differ something, for these are drawn up by the lines themselves, and the Larrum is set by turning the [Page 43] Circle of small figures, till the figure, re­presenting the hour you would have it ring at, be set under the back end of the hand; as if you would have it ring at 4 of the Clock in the morn­ing, turn the Circle about till you set the figure of 4 thereon just under the back (or shorter end of the hand,) so shall you have its desired effects, if you draw the weight of it up.

For the ordering the Clock, in re­ference to the makeing it strike true with the hand, tis the same before delivered concerning the pocket Clock; whether I refer you.

When these movements go too fast or too slow, how shall they be rectified and adjusted.

These movements going with weights must be brought to keep true time by adding to or diminishing from them: if they go too slow you must add thin shifts of lead to the weights to make it go faster, but if it go too fast then you must diminish the weight to make it go slower, so that, whenso­ever [Page 44] you find it either to gain or loose, you must thus, by adding or diminish­ing, rectifie its motion: note that these Ballance movements are exceedingly subject to be altered by the change of weather, and therefore are most commonly very trou [...]lsome to keep to a true time, except they are your pocket watches, which by reason of their being alwaies kept near the heat of a mans body, are less sensible of the alteration of Air, and so less sub­ject to be varied by it.

DIALOGVE III. Of Pendulum Clocks, their use, right ma­naging, and true adjusting.

What rules give you for the right ordering of the pen­dulum Clock.

The Pendulum Clock being the most perfect, we shall deliver the [Page 45] full order and manner of true keep­ing it; first, after you have fixed it to the place where it is to stand, you must give motion to the Pendu­lum by a touch of your finger, for it will not move of it self, but must be set one vibrating by manual operati­on, when the Pendulum is in moti­on it must not be touch't, for that will settle it still, and keep it from go­ing.

It must be pulled up by the hind-most line of the counter weight.

It must by no means be Jogged out of its place, or beaten a wrye, for that will put a stop to the motion.

How must it be ordered as to its striking?

The same way that the other Clocks were by continual lifting up of the locking detent, till you have brought the striking and the hour to­gether, did it either strike too much or too little; here take notice that the locking detent is on the right side of the Clock, if it go with one [Page 46] weight, but if it go with two weights then the locking detent is common­ly on the left side of it, as it is in ordinary Ballance Clocks; for the Ju­stening of the Pendulum, it is done by altering the Radius thereof, either lon­ger or shorter, as occasion serveth, so that if a Pendulum go too slow you must, by screwing the bob from you, shorten its Radius, which makes it vi­brate oftner and go faster, but if it goes too fast then you must screw the bob lower, by turning the bob towards you, which makes its Radius longer, and by consequence obligeth it to go slower.

When a Pendulum is once rectified will it not alter like the Bal­lance Clock?

The short Pendulum is subject to some alteration, but not so often nor Considerable as the Ballance: up­on extream foulness they have been observed to go too fast (contrary to the custome of [...]allance work▪ who is th [...]n subject to go too slow) the reason [Page 47] of its thus going too fast when foul, is the choaking of the pevets with dust, which hinder the motion of the Pendulum, and restraineth it from fetching its wonted compass, so that the Arch of its recursion being shor­tened it must needs pass it in lesser time, and so by consequence gain as to its wonted course; of which more may be understood when the Pendu­lum is treated of.

Have you nothing more to de­liver concerning Pendulums?

Nothing more concerning these ordinary ones, I confess, som­thing more might be delivered con­cerning the more richer kinds, but it being so hard to teach by precept without example, that I shall forbear. However what hath before been de­livered is of good use in their ma­nagment, as to the matter of adjusting and setting them.

Is the long pendulum subject to variation as the short one is?

No; being once brought to a [Page 48] true time it alwaies keeps it, for it mov­eth in so small an arch, that tis unpossi­ble for it to move less without stand­ing, and more it cannot being impe­ded by the work; so that being con­fined that it cannot remove more or less from its center of gravity, it must needs keep a certain motion as to it self.

But tis observed that they va­ry many times from the Sun, how can this be but from the Pendulum?

I confess there is some small difference many times between them and the sun, but this is not from the Pemdulum but from other causes which shall be treated of when I shall discourse the inequality of time and refractions.

DIALOGVE IV. Of Quarter Repeating, and Chime Clocks, their use and management.

May there be any rules giv­en for the setting, and keeping in order these motions, or may their use be known without experience?

The use of Quarter Clocks is, not onely to strike the full hour on a bell, but also to strike at the end of every Quarter of an hour, so many blows on a smaller bell as are sufficient to express the number of Quarters that have passed since the hour last struck.

Do they strike on one bell onely or on more?

They are made many times to strike the Quarters on more bells then one, as many times on 2, 3, 4, 5, or 6. but let them strike on never so many [Page 50] they must strike them over as many times each quarter, as there are quar­ters passed since the striking of the last hour.

How doth the repeating Clock strike?

They not only strike the hour and quarter, but also, immediately after the striking of each quarter, it repeats or strikes over again, on a different bell, the last hour that was strucken, by which you are given to understand, that it is 1, 2, or 3 quarters past that hour which was repeated; this Clock is of excellent use for the night.

There is another sort of repeating Clocks, which differs much from this before spoken of, the quarters and re­peating, being both performed at the same time, and on the same bells; it strikes the quarters on three bells, and the hour bell never strikes above six: to understand the striking of this Clock you must observe this rule. Look on how many quarter bells it strikes whether on 1, 2, or 3, for so [Page 51] many quarters are passed since the strikeing of the last hour, as if it strike on one bell, then one quarter is passed; if on two bells, then two quarters are passed, if on three bells, three quarters are passed: then again, look how ma­ny times it strikes on any number of the aforesaid three bells, that is the hour that was strucken last; as suppose it strike five times on two bells, this signifies its two quarters past five or eleven as the time is, again sup­pose it strike six times one three bells, this signifies its three quarters past fix or twelve, according to the time.

I understand not the meaning of its striking six or twelve, or eleven or five.

The meaning is this, the Clock never striking but six, is the cause that at seven of the Clock in the morning it strikes but one; at eight, two; and at nine three; at ten, four; at eleven, five; and at twelve, six; which every one that hath common sence cannot imagine to be six at morning, or six at [Page 52] evening, and therefore must needs be the next extream from six, viz, twelve.

How are these quarter and re­peating Clocks to be managed in their setting?

Only by the successive strik­ing them round by lifting up their locking detents so often, till each part agreeth with the other in the perform­ance of its office.

By what means may these detents be known, or how shall we find them, when there may be occasion to make use of them?

To write of these things is but in vain, for 'tis unpossible (where there is such variety) to give certain and general directions your, best know­ledg herein will be from experience and the assistance of one well instruct­ed therein.

DIALOGUE V. Certain cases to be observed in all Clocks generally.

How often do Clocks require to be cleansed?

All Clocks ought once every year to be cleansed from the filth and dirt they have contracted: they ought likewise to be once or twice oyled be­tween each cleansing, for when the pe­vets are once grown dry they wear four times as fast as otherwise they would do, if they were kept moist with a little clean oyle, and are like­wise then most subject to standing still.

Is not air and dust very Injuri­ous to a Clock?

Yes, and therefore all Clocks in the time of their going, ought to be kept as free as possible from both, the one will be apt to canker and [Page 54] rust it, the other will exceedingly clog and soul it, therefore to avoid one ill convenience in part, let those Clocks that move with lines, be sure to be alwaies sitted with those that are sound and good, for when once the lines of a Clock begin to grow any whit worn they foul a Clock ex­ceedingly.

'Tis certain I have known Clocks that for two or three years have gone well without either clean­ing or lining.

This is likewise my expe­rience, having know [...] the like both in Clocks and Watches, but this was commonly the event, that when they were forced to make them clean they never went well after, for going dry so long without oyl, they were so ex­treamly worne, that twas unpossible they should go longer.

This I fear will be the fate of those long swing eight day Pendulums, so much at this day celebrated, for so long as they keep going well other things are [Page 55] not considered, nor no regard is had to those things that should conti­nue them in that placide estate of mo­tion.

Which way must the hand be turned when we set either Clock or watch?

When you set your pocket watches to the hour your best way is to move your hand backward (or con­trary to the succession of the figures) but if your movement be a Clock then you must not turn it thus backward as you do a watch, because it will in­danger the spoiling of it, but strike it forward from hour to hour, till you come to the time you would set it at, then when you have so done put it som [...] ­thing past the time you would set it to, and then bring it back again to the true time: as if your Clock were down, and your and stood at eight, and you were to set it at a quarter past eleven; to do this strike your Clock gradually from eight to nine, and from nine to ten, and from ten to eleven; then, to [Page 56] set it at a quarter past eleven, turn it to half an hour past, and then bring it back to a quarter or the true time. The reason of this advise is, because, if you put it forward when you set the hand, it will stand still, for as long time as the shaking or playing thereof contains in time on the dial ring. I have known the hand of some Clocks and Watches, that have played forward and backward above a quarter of an hour, and so long will they stand still, and not move the needle, when they are newly set, by turning the hand forward, whereas, if according to this direction, you put it backward, it will move immediately with the rest of the work: the not understanding of this hath bread great mistakes between many a gentleman and his Watch.

Observe also to set your Watch con­tinually by one Sun-dial, because 'tis sel­dome known that two Sun-dials go true together; so that, if you set it sometimes by one, and sometimes by another, you will never know when [Page 57] your Watch or Clock goeth right. Also observe further to set it (if po­ssible) always to one hour on the same dial; because many times the hour-lines give not true time alike, which, if it should thus happen, yet setting it always at one hour, will prevent all mistakes, or at least all those that are sensible.

What must be observed when Clocks or Watches want cleansing or repairing?

They must observe and be care­ful to send it to a workman, and not bring the Workman to it: many Gentlemen are of this humour, that when they have a Clock or such like that wants cleaning or mending, the workman must come to their houses to do it, which is a great mistake, for tis impossible for a workman when he is from his tools to perform his business so exquisitly as otherwise he might, so that they that desire this are certain to have their business never well done.

I would also advise all persons what­soever [Page 58] whose Clocks or Watches want reparations, that they give suffici­ent time after they are cleansed or mended, for the work-man truly to ad­just them, for there is no man that can say, when he hath mended either Clock or Watch, that it▪ shall go true, and perform well, till he have by suf­ficient tryal proved it and adjusted it.

Is it considerable whether or no we keep a true time in winding up Watches or Clock [...]?

Not at all▪ you may wind them up at what time you please, or as often as you please, it matters not; only observe in Watches, and other spring movements to wind them till they stop, and not give over till you wi [...]d them wholly up; for if you do, you may chance to find alteration in their motion; for the spring, when first wound up, draws harder then be doth when he is somewhat settled, and if this happen in any place of the fuzey, that is not diminished propor­tionable [Page 59] to this impetuous, it must needs cause variation in the motion.

These are the most necessary, and chief directions, that can be given in writing, or that can be apprehended without example; nevertheless, who­soever is Master of either Clocks or Watches, shall certainly find great benefit by what hath been here delivered, if he be careful to observe them.

And though the rules, here deliver­ed in this second part, are not so full and general as might be expected, yet they are as full as I thought conveni­ent; for I did consider that every one, that make use of Clocks or Watches, knows also how to manage them, as to the common rules thereunto be­longing, and therefore I did think it needless to insert those things that are already so commonly known, only I did give a little touch of some of them (that are most material) for m [...] ­thods sake: for the First and Third parts, and the Appendix, was that which [Page 60] I chiefly designed, and may be worth the reading, if it be done with consi­deration; for they contain those things that are known, but to a very few, and perhaps not rightly understood by some of them, so as to apply them to use and benefit.

DIALOGVE 1. Of the inequality of time in respect of Artificial motions: the mature of it, their times of erring with the quan­tity of their error, from whence se­veral conclusions are drawn in refe­rence to Clocks

What is the ine­quality of time and wher­in doth it consist?

The inequality of time consisteth not in the unequal length of days natural but in [Page 62] the unequal length of hours, as given on a Sun-dial which is a thing little sought after, and less understood by those whom it most nearly concerns.

This is a thing I never before heard of, nor can at present understand, how the hours given can be one longer then another, that is how the shadow on a Sundial can be longer time in passing from one hour to another at one time of the year, then it is at another, for my part I never observed it, nor cannot i­magine which way to do it.

There is no way possible to observe it, but by an exact Clock, that is regulated by a large Pendulum.

What is the reason of this inequality of time?

In giving the reason or cause there is great difference, some make the reason of it to be the obliquity of the Zodiack, wherein the Sun moveth; others make the difference between the Suns true longitude, and his right ascention to be the absolute cause, others make the unequal motion of the Sun in the [Page 63] Zodiack to be the cause (which I in­cline to) but the cause of this cause, I suppose, all are ignorant of, because God in his word never revealed it, and for any other way of knowing it, I suppose, 'tis so far from our attain­ment that the wisdome of the best Astronomer will in this prove but foolishness, however they may other­wise pretend.

What reason have you to believe the Suns unequal Course to be the cause?

Because the Sun in its motion through the Zodiack passeth equal ar­ches in unequal times, by reason of its swift and slow motion whereby he ful­filleth his course from Libra to Aries in 178 days (which is the winter half-year) but in passing from Aries to Libra he takes up 187 days (which is the summer half-year) being nine dayes longer in passing through the semi [...]clip­tick of the summer, than she is through that of the winter, now the Sun being thus swift and slow in motion can­not [Page 64] give a true and constant hour by its shadow one a Sundial for the mo­tion of the primum Mobil finish­eth its course in exact times, i. e. in twenty four hours which well a­grees with the Suns mean motion near the equinoctial, but when the Sun is in its swift motion, as it happeneth when inclining to the winter Tropick, then there is more time contained in twen­ty four hours, as given on a dial, then there was in the equinoctial, and so by consequence every perticular hour in the twenty four must be somewhat longer then those in the Aequator: but when she happeneth to have slow motion as from Aries to Libra then there is not so much time contained in twenty four hours as there is in the Aequator, and so by consequence every hour must also be shorter.

How this swift and slow mo­tion of the Sun should c [...]use this ine­quality in time I cannot well under­stand.

Suppose there were on an instru­ment [Page 65] two circles drawn concentrick, and the outmost Circle should be graduated into 360 degrees, and eve­ry degree into sixty minuts, and suppose that upon this circle thus graduated, there should some certain figure move, as it were naturally from West to East, which in Twenty four hours should move almost Fifty nine minutes of a degree; suppose likewise that in this time of moving Fifty nine minutes, the innermost circle should compleatly the same way make one revolution, and should continue so to do; that is, should always compleat its revolution, within it self in Twenty four hours, in which time the other moves fifty nine minutes of a degree; then suppose this figure on the graduated circle should increase its motion, and should move Sixty one minutes of a degree, in the same time as it before moved but Fifty nine; this must needs cause the innermost circle (who before in twenty four hours finished its course from one conjunction to another, when the figure [Page 66] moved but fifty nine in twenty four hours) to be longer time now, then twenty four hours, in passing from one conjunction to another, because the fi­gure moveth faster, and so by conse­quence, requires more time to be o­vertaken then it did in its mean moti­on, the same reason is also for its slow motion; for if the figure move less then fifty nine (as suppose fifty eight or fif­ty seven minutes) there is less time re­quired for the prymoby like motion of the innermost circle to overtake it, then twenty four hours.

What do you infer from hence?

From hence we may infer, that if the hours given by a Sun-dial, increase or decrease in length, accord▪ to the slow or swift motion of the Sun, that then tis impossible for the most exact▪ [...]l [...]ck that ever was made, to keep [...]e with a Sun-dial, but there will be di [...]erence, according to the time of the y [...]r [...]d [...] of the [...]u [...].

How is it then possible to [Page 67] justen a Clock, exactly to the hour.

Tis possible (when a man rightly understands the course of the Sun) to justen it so, as that if it be set to a Sun-dial at any time it may be right with the same dial that time twelve month, but to justen it so as to keep touch with a dial the year round is unpossible.

At what time will they dif­fer?

If a Pendulum truely adjust­ed (so as to come right that time twelve month without setting) be set to the hour in January, it shall in June following be too slow by the same dial; if it be set in June to the hour, in January following, it shall be too fast, but if it be let go the year round, it shall in one half year gain or lose what it lost or got in the other, and so at the years end come right to the time it was first set at.

What may be the quantity of their error?

[Page 68]

From June to January (if it be well adjusted) twill nevertheless gain about forty four minutes, or almost three quarters of an hour; from January to June twill lose near the same time; if set to a dial in March, it may lose by June something above a quarter of an hour, viz, twenty two minutes; from Iune to September twill gain as much and come right again; from September to December it will gain about twenty two minutes, but from December to March twill lose it and come right again, Whence observe that Clocks set to the hour, when the Sun is in either of the tropicks, continues gain­ing and losing the whole year round, and never agree with the same dial, till that time twelve month: but if they are set when the Sun is in ei­ther of the equinoctial points, then they may agree with the same dial twice in the same time or year, and their gaining and losing will never be so extream, as when set in the [Page 69] tropicks, for if be set in March (or the equinoctial of Aries) it shall have lost in Iune but twenty one or twenty two minutes, and in September following it will agree with the same dial again, from thence to December twill gain as much, and from thence to March it will lose it and come right again; so that from hence we may likewise con­clude that those Clocks, which go to a quarter of an hour or something more in three months, are the near­est that can be brought to keep true time with the Sun, let them be of what form, kind, or price soever.

What is the most true and exact way of justening Clocks by the Sun?

If you would justen a Clock exactly to the Sun, so that a twelve month after it may agree with the same dial (if set when the Sun is in the tropicks, or agree with the same dial twice in the year, when set in the equinoctials) do thus, in the equinox of March let it be set to a true [Page 70] dial that sheweth minutes, and when the Sun is in the meridian; then in Iune following observe the difference between your Clock and dial, which if it be about twenty two minutes too slow then conclude it goeth well▪ but if it be more then twenty two minutes or less, then you must rectifie it accord­ingly, as hath been formerly taught, and thus you may rectifie it, according to any other time, if you consider the dif­ference that happeneth after so many months going, from any time of setting.

DIALOGVE II. Of Refractions what it is, and when it happeneth, with several conclusions drawn from it, in reference to Clocks.

What is the refraction of the Suns beams, and how is it caused?

Refraction of the Sun is when [Page 71] she appeareth higher in altitude then indeed she is, and is caused by the moist and humid vapours which con­tinually arise from off the earth, which naturally do represent all things, that are seen through them, to be larger in bulk and higher in altitude then indeed they really are, this makes the Sun, Moon, and Stars▪ when they first arise, to appear so large in magnitude, which continually diminisheth according as they ascend above the horizon, till being elevated above all vap [...]urs, they are again reduced in our appearance to their natuaral magnitude, and as those vapours make them appear to us of greater bulk and magnitude then otherwise they would, so they cause them also to appear higher in altitude: so that we see the sun visi­bly risen before she is naturally above the horizon.

How is this proved?

It may be proved thus: take an Horizontal Dial, that is large and truly drawn, place it exactly in its [Page 72] true position, which having done, let a Pendulum Clock, that keepeth true time, be (about twelve of the Clock) set exactly to it; the next morning, if the Sun shine, observe how they agree, and you shall find that at the first rising of the Sun there will be much diffe­rence, which will by little and little diminish, according as the Sun gets above the strength of those vapours, till at last they come exactly together, which could not be, if her altitude were not by these refractions, made apparently higher than her true place.

What conclusions may be drawn from hence?

Since it is so that those vapors make the Sun at his rising or setting to appear higher to us than naturally she is, this must by consequence give a false shaddow on all Sun-dials, both at its rising and setting, because the hour lines drawn on Sun-dials, are designed to receive the shaddow of the Sun from its true place, and not from his appatient; and so by consequence all [Page 73] Dials whatsoever cannot at those times give the true hour, because they re­ceive not their shaddow from the Suns true place, but from his apparient; therefore if your Watches and Clocks agree not with your Dial, you are not to conclude the fault to be in their mo­tion (if they have gone well before) but in the refracted shining of the Sun.

What altitude may the Sun at­tain before we may put confidence in a Sun-dial?

For this I shall give you a Table made by my observation as near as possible to the truth.

[Page 74]

The use of this Table is thus, first find the Suns altitude in the lest hand column, intituled ⊙ alti­tude, and right against it you have the minutes and s [...]cants, which those dials vary when the Sun hath such degrees of altitude; as for ex­ample, when the Sun first appeareth, [Page 75] a dial will differ from the true time 18 minutes; when she hath 3 degrees of altitude, the difference is 9 minutes; when she hath 9 degrees of altitude, the difference is 5 minutes 30 se­cants, &c. so that it will not be safe setting either Watch or Clock to the hour given on a Sun-dial, till the Sun have attained 20 degrees of altitude above the Horizon, till which time the refraction is something sensible.

Tell me precisely what hours are fittest for that purpose?

The best times for setting either Clock or watch to the time, on a Dial, is in May, Iune, and Iuly, between the hours of 7 in the morning and 5 in the afternoon, in April and August between the hours of 8 in the morning, and 4. in the afternoon; in February and September, between the hours of 10 and 2, the other months 'twill not be safe setting them till near noon.

Suppose a watch should be set to a Sun-dial betimes in the morning, what then?

[Page 76]

Then it will not go right with the same Dial all the prime part of the day after, but will differ as much as the refraction was, when it was set to the same dial.

are not these refractions al­ways equal throughout the year?

No, they are greater in Win­ter than in the Summer, greater in moist weather than in dry, greater near Seas or large Rivers than on the remoter parts of dry land, and grea­ter in the morning than they are in the evening, all which being duly consi­dered, may prove of good use for the business for which this discourse hath designed it, viz. The true keeping, and right managing of all Clocks and Watches whatsoever; so that when­soever you shall find your Watches or Clocks differ in the same day from your Dial, you may by knowing the reason of it prevent those mistakes which otherwise might arise?

DIALOGVE III. Of the Spring, its definition, nature and defects, with the effects thereof in Clocks and Watches.

From whence do those Movements that go without weights receive their motion?

From a spring.

What is a spring?

A spring is a certain thin plate of steel, drawn by the hammer to a sufficient length, breadth, and thickness, according as the proportion of draught (which is designed to it re­quires) this being exactly wrought, and artificially tempered, is wound up in the form of a spiral line, not close together, but at a certain distance, after which it is conveyed into its barrel, where it lyeth something clo­ser together in the outward circumfe­rence than in the center, having the [Page 78] one end fastened to the barrel, and the other to the arbor whereon the bar­rel moveth.

When it is thus sitted to its work, how doth it perform or draw, so as to give motion to the wheels after it is wound up?

When it is first wound up, it compresseth it self in the center, (as▪ before it did in the circumference) but being by the temper made as it were free Deniz [...]n of a certain Orb, it ne­ver resteth till by extension it hath a [...]ained to its first place, which it doth not in an instant, but by degrees as the motion of the work, which it draws along with it, will suffer it to move round.

Is the draught of a spring equally in a [...]l places alike, or doth it differ according as it may be str [...]ned?

The spring is always strongest when first wound up, and weakest when returned to its natural posi­tion; from whence it happeneth that [Page 79] the fuzey (by which the spring draw­eth the work about) is made com­monly in the shape of a Counical screw, by which means this unequal draught is regulated and made alike equal; for when the spring is first wound up, and its draught strongest, there the fuzey is least, and so as the strength of the spring decreaseth, so the bigness of the fuzey increaseth, by which means the wheels move most commonly with a pretty equal mo­tion.

Is it possible so to adjust a fu­zey to the draught of a spring, that there shall be no alteration of time in those Watches which it moveth?

The answer to this your que­stion is a thing of great consequence, and deserves diligently to be enquired into: my opinion is, that the spring like a wise Master-fencer, hath re­served to himself some certain un­lucky tricks (which it's most dili­gent observers cannot attain to the knowledge of) that so it may be able [Page 80] on occasion to give a foil to those that think themselves sufficiently able to overcome all its difficulties: Certain it is that those occult defects, which are yet remaining in the spring, are the very scourge and disgrace of Clock-makers, working those effects in the motion of Watches, which the most sound workman is not able to remedy, it being equally as unpossible to make a Watch go always true, as to have light and darkness both in the same place at the same time.

Some Watches there are that for 6 or 8 days will go indifferent right, and after that it may be check and go too slow, and another time too fast, and seldom continue in one estate of mo­tion, although it have always one bent offspring; this is often remedied with a new spring, but never with the same.

Others there are that shall never go well 24 hours together, but shall either gain or lose in spite of Art.

Springs many times draw well for a time, and then faulter at last, as is [Page 81] seen in many new Watches, who go well when first sold, but afterward upon settling of the spring; have moved very irregularly, which may be recti­fied by another new spring; however the Work-man is commonly on such occasions blamed, though the fault be none of his, but is rather (if in any) the fault of the spring-maker.

How is it the Spring-makers fault?

Either he worketh them not truly to an equal thickness, or giveth them not a true temper in all places alike, or it may be leaveth them too high, or taketh them down too low, all which may be the cause of their unpla­cent motion; for if they compress themselves more in one place than in another, it cannot in its extension move so free from jerking or twitch­ing, as those that are compressed alike in all its parts, which illconveniencies though they many times are caused through the Spring-makers neglect, yet I date not affirm it to be always his [Page 82] fault; for I believe, let them take all the care that possibly they can, yet the nature of steel is such, that it will not in all places take temper alike, which how the best work-man in this way will be able to remedy, I know not; however it is certain, that where a spring is wrought with care, let it be what steel it will, yet it must needs prove better than those that are wrought with neglect.

Are all springs troubled with those defects?

No, all are not, in so high a measure, for then 'twere unpossible any Watches should go true. Some are far better than others, and by chance a man may light on some that are pure­ly good, but this is very rare, but for the most part, they are either more or less defective, and so by consequence those Watches that are moved by them, keep either a certain or uncer­tain time, according as the springs are in goodness that move them, al­ways having consideration to the [Page 83] goodness of the work; from all which we may conclude that the pains and care of Watch-makers ought to be very great that bring those Movements to any true performance, and if those that buy them, were as careful to pay them for their trouble, it would in this Art produce great effects.

Let me advise all Gentlemen (and others) whose fortune it hath been to light on those Watches, that by the care of a good Workman, are brought to perform well, that they value them accordingly, and take great care that they do not by violence put them into disorder, it's possible that a Watch may go near the true time, though not set in many days, this account ex­cellent; but if it go so well as to re­quire setting but in two or three days, this is very considerable; and where you have one that goes better you may have two that go worse; there­fore prise these also, and account that work that performs thus▪ to be good work, and carefully finished.

[Page 84]Note, That Pendulum Clocks or Watches which are drawn by springs, are not subject to those irregular mo­tions as ballance movements are.

DIALOGVE IV. Some Enquiries into the Nature of the Pendulum, with the method of find­ing their several lengths.

The Pendulum being one of the most exact means yet disco­vered for the keeping of true time, it would be time well spent to enquire something into the nature of its mo­tion, both as to its vibrations and terms of suspension.

As for the vibration of Pen­dulums suspended at any length, 'tis certain that the times of it, vibrations natural to any Pendulums length, are so limited and prefixed, that it is im­possible to make it move under any [Page 85] other period than that only one, which is natural unto it, let any one try all the ways he can to encrease or decrease the frequency of its vibrations, and he shall find his labour all in vain, pro­vided he encrease or decrease not the arch of its recursions; that is, that he remove it not farther or lesser from its Center of gravity, than such a certain number of degrees.

You need not have made any exception, for tis well demonstrated by one of the Ancients, that if it be removed from the Center of gravity, any number of degrees whatsoever from one to ninety, yet the number of vibrations in the same Pendulum shall not encrease or decrease: His words are these, ‘That the Moveables that should descend along the Cords, that are Subtenses to any Arch, must ne­cessarily pass them all in equal times, as well the subtense under an hundred an eighty degrees (that is the whole Diameter) as the subtenses of an hun­dred, sixty, ten, two, or half a degree, [Page 86] four minutes: still supposing that they all determine in the lowest point touching the Horizontal plain.’ An effect which hath in it so much of won­der, by how much at the first appre­hension one would think the contrary would follow; for the term of the beginning and end of the motion being common▪ and the right line being the shortest that can be comprehended be­tween the said terms, it seemeth rea­sonable that the motion made by it should be finished in the shortest time, which yet is not so, but the shortest time, and consequently the swiftest motion, is that made by the Arch, of which the said right line is Cord.

But if this ancient Writer had had the same opportunity of ex­periencing these things as we have now, he would have been of another opinion: For to confute this, tryal was made by a Pendulum about seven foot long, which vibrated (by a Clock shewing secants) 41 times in a mi­nute, at which time it swong or moved [Page 87] in an Arch of four inches, the same Pendulum, at 12 inches Arch vibrated but 40 ¼ the same at 10 foot Arch vi­brated but 39 times, the same Pendu­lum at the whole Semi-arch vibrated but 37 times, so that here was four blows difference in the same Pendu­lum, when vibrating in different arches, which clearly prove that Pendulums cannot perform all its vibrations great, lesser, and least, under times precisely equal.

Besides, 'tis clearly apparent that ordinary pendulum Clocks and others, whose pendants are but short, that when through foulness or natural wea­ring, they fetch not so large a com­pass as when they are clean, and in order 'tis then I say apparent that their motion is swifter than at other times.

It's probable that your Me­chanical observations may be of more weight than the best rules of Art in this kind, for the truth is, if rules of Art will not keep touch with the Mecha­nicks, [Page 88] 'tis not to be regarded; in the next place let us consider the vibra­tions of Pendulums of different lengths in the same time, what propor­tions they beat?

As to the times of the vibra­tions of pendulums suspended by ver­ges of different lengths, those times are in subduple proportion to the the lengths of their verges, or if you will, the lengths are in duplicate pro­portion to the times; that is, are as the squares of the times: so that if for example the time of the vibration of one pendulum is double to the vibra­tion of an other, it followeth that the length of the rod of that is quadruple to the length of the verge of this, and in the time of one vibration of that, another shall make three vibrations when the verge of that shall be nine times as long as the other. From whence doth follow, that the length of the verges have to each other the the same proportion as the squares of the number of vibrations that are made in the same times have.

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Then if I have rightly under­stood you, I may easily know the length of a pendulum hanging at never so great heighth, although the sub­lime term of suspension were invisible to me, and I only saw the lower ex­tream, for if it should be set on vibrating too and again, and a friend telling some of its recursions, and I at the same time tell the recursions of another pendulum suspended, on a verge precisely a yard long, by the numbers of the vibrations of these pendulums made in the same time: I will find the length of the pendulum whose term of suspension I know not, as for example, suppose in the time that my friend hath counted twenty recursions of the long pendulum, and I had told two hundred and forty of mine that is a yard long: squaring the two numbers of 20 and 240. which are 400 and 57600. I will say that the long string containeth 57600 of those measures of which my string containeth 400.

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You are in the right, nor will you be mistaken one inch, especially if you take a great number of vibra­tions: by the same rule also you may (having the length of any one pendu­lum from its upmost suspension to the Center of the bob, and the number of its vibrations in a minute) find out the length of a pendulum that shall vibrate any number of blows in the same time; suppose I had a pendent three foot long that vibrated 62 times in a minute, and I have occasion for to find out the length of a pendulum that shall vibrate but 20 in a minute. Do thus, square the two numbers 62 and 20, which produce 3844 and 400, now divide 3844 by 400, the quotient is 9 61/100 therefore I say that this pendulum to vibrat 20 in one minute, must be 9 61/100 times as long as my standard pendu­lum, which being 3 foot, the other will be 28 foot 8 inches long from the term of suspension to the center of the bob, and thus you may do for any o­ther whatsoever, by observing what [Page 91] hath been here delivered. For so often as the square of any number of vibra­tions is contained in the square of a­nother made in the same time, so many times must the length of that pendulum (which made the greatest square) be contained in the length of the other which made the smaller square.

By the same rule inverted, you may, by having the lengths of two pendu­lums, and the vibrations that one of them makes in a minute, find out also the times that the other shall vibrate in the same time: for if you have a pen­dulum whose number of vibrations in a minute you know already, and would know the vibrations that another pen­dulum, which is longer, shall make in the same time: Consider how often the length of your short pendulum is contained in that longer pendulum, and so often shall the squares of that long pendulums vibrations be contain­ed in the squares of those vibrations made by the short pendulum in the same time: So likewise if you have a [Page 26] long pendulum whose vibrations you know, and you would know how many vibrations a pendulum that is shorter, shall make in the same time, look how much your first pendulum is longer than your short one: so many times greater must the square of your short pendulums vibrations be above those made by your longer pendulum in the same time.

Note, that great care ought to be had in taking the true length of your pendulum, from the utmost term of sus­pension to the center of the bob, and likewise that your pendulums bobs be of an equal weight, or reduced there­unto by rules of proportion.

DIALOGVE V. Of the Clock-bell, the cause of its sounding, with the nature thereof, proved by reason and experience.

The nature of sounds in my opinion, is one of the most sub­tle pieces of nature, being equally mysterious with that of light and co­lours, and a thing that hitherto hath been but superficially observed, and as yet very little minded, and though we cannot expect the true reasons thereof can be soon attained, yet to make some certain enquiry thereinto will not be time mispent; therefore to come the more close to our intended design, what is your opinion concerning the first creation of sound in a Clock-bell.

Air▪ being the most pure Me­dium of all sounds, must be wrought upon by such means as are solely ne­cessary for the creation of a sound, [Page 94] which will be effected, if tortured by most quick and subtile motions; hence it happeneth that Bells, having by means of the percussion of the hammer, a trembling wrought in the minute parts, which by its quick and subtile working upon the air in the concavity of the Bell, produceth a tone or sound.

What is the reason of the trebbleness or baseness of tones, one above another.

The trebbleness or baseness of tones in Bells, is from two causes; First, from the quantity of air that is p [...]rcused or contained in the concavity of the Ball Secondly, from the quickness or slowness of the percu­sion. To prove this, take Bells of different greatness, but the same thick­ness in metal, and you shall find them to produce different tones, according to the quantity of air contained in their concavities Again, take Bells of the same bredth and depth, but differing in their metal, and you shall find that [Page 95] Bell whose metal is thinnest, to give the most base sound, and those that are thickest in metal, shall produce the most treble sound; for the thicker the Bell is, the more quick and sharp is the percusion of the air within it, which produceth the treble tone, but the thinner the Bell, the more weak and slow is the percusion, which accor­ding to its nature, produceth a more base or flat tone.

Tones are the same in Bells of se­veral weights, but differently majo­rated according to the magnitude of their bodies that produce it, for you shall have a Bell of a pound weight carry the same tone as a Bell of two or three hundred, but not in the same strength to be heard so far; so likewise it's possible that a Bell of ten pound weight may produce the same tone as a Bell of four or five thousand weight, but yet their different majoration will be according to the proportion of their metals.

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May not the sound of two Bells of the same weight be different in majoration, that is to be heard, one farther than another.

Yes, 'tis certain they may; for always observe, the sharper the tone is, the farther the sound is heard, being more active and sprightly than those tones that have a more dull and solitary note; from Bells of the same weight.

From what hath been delivered, it will be worth the while to draw some heads of enquity.

First, what just proportion of air in the concavity of a Bell, shall be sufficient to produce a whole Musical tone, and what proportion will hold in every tone.

Secondly, what diminution of sub­stance in a bell of any weight, will be sufficient to make that Bell a tone more bas [...]? or what diminution of depth shall be sufficient to make it a note sharper?

Thirdly, what bore a Bell of any weight requires to majorate the sound [Page 97] thereof to the highest degree possi­ble?

How do sounds of Bells spread or move in the air?

All sounds of Bells spread themselves into a spherical area, where there is no impediment; otherwise they move more oval, if carried by the violence of winds, or otherwise obstru­cted.

Though sounds of Bells spread them­selves spherically, yet they go farthest in the fore lines from the first local im­pulsion of the air.

All reflections concurrent, make sounds greater (but if the body that createth the reflection be clean and smooth, it maketh them sweeter) as is seen in large and stately Halls or Chur­ches, where the least voice is soon heard.

Soft and foraminous bodies in the first Creation of the sound of Bells, will dead it, as is apparent where hangings are used, but in passage of sounds, they will admit it better than hard bodies.

[Page 98] Querie.Whether the sound of Clock bells may not be majorated by means of its passage through certain trunks on purpose artificially placed for the sound to pass through, that by the penning thereof it may come forth more strong and loud, this would be a thing of excellent use, if it could be effected?

Querie also. What weight of Ham­mer is best for to make the Bell give forth its true and natural sound? for 'tis observed, that if the Hammer be too heavy or too light for that quantity or quality of metal contained in a Bell, they give not their sound so clear and full as when due proportion is obser­ved.