DESCRIPTION OF THE PRINCIPLES AND PLAN OF PROPOSED ESTABLISHMENTS OF SALT WORKS, &c.
DESCRIPTION OF THE PRINCIPLES AND PLAN OF PROPOSED ESTABLISHMENTS OF SALT WORKS; FOR THE PURPOSE OF SUPPLYING THE UNITED STATES WITH HOME MADE SALT.
BY JAMES FENNELL.
PHILADELPHIA: PRINTED BY JOHN BIOREN.
MDCCXCVIII.
TO JOHN ADAMS PRESIDENT OF THE UNITED STATES:
From a conviction that every object which tends to promote or secure the independence and happiness of the United States must be interesting to your mind, I take the liberty of dedicating to you the following fruits of a series of laborious and repeated experiments.
PREFACE TO THE READER.
I HAVE three reasons for publishing what follows: The first, originates in a desire to obviate those unfavourable impressions which the suggestions of ignorance and prejudice have caused respecting the works which are the subject of this treatise, and to exhibit my plans to the judgment of sensible men, such as they really are.
The second, originates in a hope that in consequence of the success of the abovementioned desire, I may induce others to become adventurers in an undertaking, which in its promise of advantages embraces every individual in the union.
The third, though the least personally advantageous, not the least impressive on my mind, results from a hope of being of some service to the country in which I live.
[Page 8] While I am writing this preface, I think I may venture to assert, that there are not six men in the world who are perfectly acquainted with the principles upon which this undertaking has been founded; yet has it been in the mouths of thousands a subject of decided disapprobation, censure and ridicule; many who have even disavowed having the smallest idea of the plan, have with a directorial assurance denounced the attempt in general as fruitless, and some have meanly dared to insinuate that I have adopted it as the vehicle of imposition on the public, and the forerunner of deception and fraud.
During a series of four years I have made the establishment of Salt Works in the United States, the primary object of my wishes, and every intervening employment (the variety of which has sometimes subjected me to the imputation of instability,) I have made subservient, to this one great object,—with an unshaken perseverance, frequently thought blameable, I have pursued it through innumerable obstacles, and under the most distressing embarrassments; and firmly confident of the eventual success, and the propriety of my own intentions, I will pursue it while I have life and sense, were it even possible that the difficulties [Page 9] I have already experienced from the pursuit could be ten times trebled to oppose me.
In the flood tide of discouraging opinions, in the storms of insolent and insulting suggestions, I have erected my judgment and my integrity as my rock of rest. I have patiently suffered the waves to beat with violence against them in the most implicit confidence, that I shall one day or other withdraw them from the tempest perfectly honoured and uninjured. The object I am in pursuit of is great; necessity, every child is told, and truly so, is the mother of invention; (I confess it so of mine), and it, consequently, not unfrequently happens that where inventive minds allow the imagination free scope, the most extensive plans are conceived by persons the least capable of executing them.
For the execution of my design I want money, and friends to the undertaking; if I procure them by this publication, my grand obstacle will be removed; and adventurers are hereby invited by an assurance on my part, of a conviction founded on experience, that the works will succeed at least so far as to yield such a profit as any reasonable man will be contented with.
[Page 10] If the following plan should be deemed by sensible men to be founded on philosophical principles and reasonable prospects of success, a question will naturally occur, how so much time could have elapsed without my having placed myself in a situation to extend the works without the necessity of publishing to convince the world of their utility; I can only here remark, that I am unwilling to trouble the public with what does not concern them; but if any person, thinking favourably of the undertaking, should wish for further satisfaction than what is contained in this publication, I shall at any time be ready to make it the subject of private communication.
Much might be urged on the political necessity of having such establishments within the United States, but the advantages thereof are too obvious to every thinking mind to need any dilate discussion; the price of salt consequent on the difficulty of procuring it during the last war is fresh in the memory of every American, and the impossibility of its being dispensed with, is a consideration that should encourage such undertakings upon terms much less favourable than those here proposed.
It is my wish that the undertaking, if approved of, should be forwarded by the purchase of shares [Page 11] entitling the holders thereof to the delivery of an ascertained quantity of salt every year for ten years, that after the expiration of that term the claims of the purchasers should cease on the payment of a stipulated sum by me, or my assigns.
It is my intention in order to accommodate all ranks of purchasers to issue these shares, in small portions, entitling the holders thereof to one hundred bushels per year for each; These shares will be delivered by me, at first, at 150 dollars each—100 dollars payable by the purchaser on the delivery of each share, and 50 dollars on the [...] delivery of the 1st 100 bushels of salt.
Reserving to myself the privilege at all times, in case of accidents, of remitting to the share holders, or their agents, cash at the rate of 75 per bushel for the quantity of salt due.
As the works progress, and the security of the shares becomes better ascertained, they will naturally rise in value and find their market price.
The number of shares issued by me or my agents at 150 dollars per share, shall not exceed two hundred. After these shall have been sold, the price of future shares will be raised as circumstances [Page 12] shall direct, and when fixed in price and number, public notice thereof shall be given to the original subscribers, and during a stipulated period they shall be allowed the exclusive privilege of purchase; after the expiration of which period the sale of the remaining shares shall be public.
Drawings of the works to which the following pages have reference are left at Mr. Shaw's medicinal warehouse Chesnut St. near the corner of 4th Street, where further explanations, if necessary, may be had.
My whole plan and intentions are now laid open to the public; if they think proper to encourage the undertaking, I have no doubt but that in the course of a few years, the United States may be furnished with salt from their own factories at as cheap, or perhaps a much cheaper rate, to every individual than that at which it is now purchased.
SPECIFICATION of the Principles and Plan of a newly invented Machine for procuring Salt from Sea water or Salt springs, by JAMES FENNELL, citizen of the State of Pennsylvania.
THE principle upon which this machine is founded, is that of producing the speediest evaporation of the fresh particles of sea water or brine without the use of fire. This is effected through the medium of sand which operates in the three following capacities, viz.
1st, As a retainer; by reserving when wetted with salt water a certain portion of it.
2dly, As a destroyer of cohesion, by separating the particles of sea water.
3dly, As an evaporator, by its natural repulsion of water, and by offering a greater quantity of surface thereof to the action of the Sun and Air.
This being the principle. Ten (more or less) wooden vats are constructed in a regular line, the one about a foot lower than the other, so that [Page 18] the water may empty itself with ease from the first into the second, and so on. These vats are furnished with two (or more) reservoirs, the one for the purpose of having always a quantity of salt water in readiness, of sufficient height to command the whole of the works; the other, for the purpose of receiving the brine from the last vat, and keeping a supply of it in readiness for crystallization. The bottom of each vat is covered with sea sand, small gravel, or fine earth, about three inches deep.
The sand is for the purpose, of retaining in each vat when wetted a certain portion of sea water, and when raked and stirred about, of exposing the fresh particles thereof to evaporation; the salt remaining with the sand.
When, in consequence of frequent wettings and dryings, the sand becomes considerably impregnated with salt, the salt is extracted by washing the sand, by passing a quantity of sea water through each vat, from first to last, and raking and stirring up the sand and water in each as it passes, thereby making it dissolve the salt left with the sand in each, till, by repeated accumulations, it becomes in the last vat saturated with salt; when [Page 19] it is drawn off into a covered reservoir, there to remain till all impurities have subsided; when, in fine weather it is drawn off, by such portions as are requisite, into a large shallow vat called a crystallizing canal, where, after being exposed a few hours it begins to crystallize, and the salt is removed at pleasure.
The principal always remaining the same, the number, size, and form of the vats may be varied as local or other circumstances require.
PLAN, and Description of a newly invented Machine for procuring Salt from the Sea water or Salt springs, with the Method of Working it; Observations &c. by JAMES FENNELL, Citizen of the State of Pennsylvania.
IT is necessary to premise that it would be attended with great difficulty, to exhibit one plan which would be suitable to all situations—local circumstances, such as inequality in the height of banks, differing positions of shores, and other causes may render requisite considerable variations in the construction of the works, and the relative positions of the vats, pond, pumps, reservoirs &c. The principle, however, upon which this plan is founded, will remain the same under every variation in the mode of building. The most concise and explicit plan is therefore adopted here, supposing the works to be erected on a level bank from six to twenty feet above the surface of the water.
The following description is divided into three subjects, viz. Explanation of the plan of the [Page 21] buildings, with references to, and observations on each part thereof.
Method of working the Machinery.
And observations on the most effectual mode of regulating the work, of profiting by the casual advantages of good weather, and lessening the casual disadvantages of bad weather.
EXPLANATION OF THE PLAN OF THE WORKS.
The Works consist of
(A) A Pond. This pond is for the purpose of receiving the sea water, at high tide, and retaining a sufficient quantity thereof for the use of the works. By means of this pond, the works may, at the most convenient times, be supplied with the best sea water; and the natural evaporation therefrom during a period of fine weather, will considerably strengthen the water, and consequently enable the same quantity to yield more salt, than if immediately taken from the sea or river.
[Page 22] (B), A pump. * This pump communicates with the pond, by means of a spout or tube; and is for the purpose of raising the water into the reservoir (C).
(C,) A reservoir, into which the water is raised from the pond; this reservoir, being sheltered from the rains by the one above it, secures the water which has been strengthened in the pond, and being by one half nearer the pond than the other, the same force will secure double the quantity of water in the time requisite to raise it to the upper reservoir. And as the usual time for filling this reservoir will be on the apparent approach of rain, after the water has been strengthened by a continuance of fine weather, the nearer it can be brought to the level of the pond the better; that the necessary quantity of water may be the sooner secured; and both reservoirs being covered (though not so represented in the drawing,) the upper one may be being filled during the continuance of misty or rainy weather, at which time [Page 23] the horse and man will have no other occupation in the works.
(D), A pump communicating with the lower reservoir and drawing the water therefrom into the upper reservoir (E).
(E), The upper reservoir of sufficient height to command the whole of the works. In this reservoir, (which is covered,) a regular quantity of water is to be kept for the supply of the vats.
(F), Ten vats, about sixteen inches deep, the one lower than the other, so as to suffer the water to run off from the first to the second and so on. The bottoms of these vats are covered with sea sand about three inches deep regularly spread over them.
(G), A horse, and rake or fine harrow; this machine is for the purpose 1st. of stirring together the sand and water to enable the water the more effectually and speedily to dissolve the salt previously left with the sand; and 2dly, after the water is drawn off, to rake the sand into little ridges, thereby exposing the greatest possible quantity of moist grains thereof to the action of [Page 24] the sun and air, and promoting the evaporation of the fresh particles of the sea water.
(H), A reservoir, to receive the brine saturated by the accumulation of saline particles during the passage of the water through the vats. In this reservoir, (which has temporary covers,) the brine is left to settle and deposit its impurities, and is thence drawn off as wanted into the crystallizing canal (I).
(I), The crystallizing canal, (with sliding covers) into which the brine is let in fair weather for the purpose of extracting the salt. The brine, if perfectly saturated, being let into this canal about two inches deep on a fine warm day, will begin to crystallize in the course of a few hours and continue so to do till night, when, if the salt is wanted fine, it must be taken out; if coarse, a greater depth of brine must be admitted, and the salt suffered to crystallize unmolested for several days, care being taken every evening, and on the approach of rain, to cover the canal from the dews and bad weather.
(K), The warehouse, into which the salt is taken from the crystallizing canal. (L), The wharf.
[Page 25] The plan being drawn chiefly for the exemplification of the principle; it was thought necessary to exhibit it in the most simple shape; therefore, the little necessary appendages, which must be obvious to every mind, and which would only have created confusion in the drawing, have been omitted; such as, the covers to the reservoirs, the spouts, frames for the pumps, &c. &c. For the same reason one crystallizing canal only is in the plan, whereas it is necessary to have ten of the size of one vat, or one containing as many square feet as are contained in all the vats, that the crystallization may keep pace with the saturation of the water.
METHOD OF WORKING THE MACHINES.
WHILE describing the method of working the machines, I will suppose a regular succession of fine weather for several days, and afterwards observe on the consequences of rain, &c.
Previously to the commencement of the regular process, the works must be prepared in the following manner, viz.
The bottoms of the vats must be covered with sand about three inches deep regularly spread over them.
That done, the pond must be filled with water let in from the river by a sluice, which must be then stopped, and the reservoirs supplied with salt water.
That being done, the first vat must be supplied with water to the depth of nine inches (or there [Page 27] about) above the sand; (this quantity of water will be about sufficient to reach and wet the last; as the sand in each vat will absorb and retain about one third of its bulk of water, viz. one inch). The water must then be drawn off from the first into the second, thence, into the third, and so on; the water will be found to diminish as it progresses, one inch in each vat, and by the tenth all that has reached it will be absorbed.
The vats being all wetted in this manner; the sand is immediately raked into ridges by the horse and machine (G), passing from one vat to the other, and is then left to dry *. The horse is then taken from the harrow and put to the pump, to supply the reservoirs with the quantity of water used in wetting the vats, of which the fresh particles evaporate, the sand becomes dry, and impregnated with salt.
This process of wetting and raking the sand, and re-supplying the reservoirs is the business of the first day. The same process must be repeated (for the sand will generally dry once in four and twenty hours) four or five days successively, after [Page 28] which the sand will be sufficiently impregnated with salt for the commencement of the regular work of making salt, which is as follows.
N. B. In describing the following process, I will, (to avoid interrupting remarks), suppose the weather to be regularly good, and the sand to dry once every day, and will hereafter observe on contingent circumstances.
The first thing in the morning, the man attaches the horse to the harrow in vat No. 1; then lets into the vat from the reservoir (E) one inch more water than on the preceding days, so that when every vat has been worked there may be one inch of water remaining in the last. The vat No. 1 being thus supplied with water, the man drives the horse up and down the vat, raking and stirring up the sand and water together, that the water may dissolve the salt left with the sand from the preceding dryings: this being accomplished, the man removes the harrow to the second vat, and draws off into that the water so strengthened with salt; here, the water, diminished in quantity but increased in strength, receives an additional supply of salt, by dissolving what it finds in the second vat: it is then let into the third vat, and so on, the same process [Page 29] continued in each, till the water having increased in strength in proportion as it diminished in quantity, what remains unabsorbed by the sand after having been admitted into the tenth vat, will have become perfectly saturated with salt, or what is commonly called brine. It is then let off into the covered reservoir (H) where having remained some time for the impurities to subside, it is drawn off into the crystallizing canal, and in the course of an hour or two the salt begins to crystallize.
During the intervals of leisure from the vats, the man and horse are employed in raising water for the supply of the reservoirs.
If the salt is wanted fine, it is taken from the crystallizing canal the first evening after crystallization, and conveyed to the warehouse: if wanted coarse, the canal must be covered at night and the salt suffered to crystallize uninterruptedly for several days.
The above described process is continued regularly every fine day, and by it a regular quantity of salt is obtained according to the size of the vats every day during fine weather.
[Page 30] One industrious man properly instructed in the management of the business, with one good horse may with ease do all the work necessary for machinery that will yield one hundred bushels of salt to the store per day on the average throughout the year. This remark will be more fully illustrated, and proved, by the following observations on the most effectual mode of regulating the work.
OBSERVATIONS
On the most effectual mode of regulating the Work; of profiting by the casual advantages of fine weather, and lessening the casual disadvantages of bad weather.
It is readily admitted that the process of conducting works on the foregoing plan, is subject to very great irregularities from the vicissitudes to which the climate is liable; it is also admitted that the management of them should be intrusted only to a person perfectly acquainted with those branches of natural philosophy implicated by such an establishment; a person, capable of calculating, of reasoning, and forming an accurate judgment of those causes and events, which may co-operate with, or militate against the end contemplated.
A complete knowledge of the subject, can alone form the basis of a sound conduct; that complete knowledge, involves information of so various a nature, that the discussion thereof would induce a dissertation too diffuse for the purpose designed here. I shall, therefore, content myself [Page 32] with observing on the principal circumstances to be attended to, without entering into an elaborate lecture on those branches of science requisite to turn such circumstances to the greatest advantage; supposing in every one concerned that intelligence necessary for the adoption of measures advised.
THE POND
Offers itself as the first object of consideration.
The general intention of this pond involves two purposes.
1st, That of having a quantity of good water always at hand for the supply of the works.
2dly, That of profiting by every opportunity afforded by a continuance of fine weather, of suffering the water to strengthen therein as much as possible.
Any persons accustomed to make observations on the winds and weather, may judge pretty accurately at any time, of the kind of weather about to prevail for a few days to come. The tides at different places are heightened by different winds; [Page 33] and the higher the tides in places contiguous to the sea, the stronger the water. By such calculations the quantity of water to be admitted into the pond, and the times of admission are to be regulated.
For instance, (and in mentioning this instance, I will suppose the situation of all others the most difficult to judge in.) Imagine the works to be erected on an inlet, bay, or river, where the Easterly wind produces the highest tides. It would in that case be imprudent to admit water to the pond during the prevalence of a South or North Wester; unless water was immediately wanted, under all disadvantages, which care should be taken to prevent.
Again—easterly winds in this country, are generally attended with rain, and are of several days continuance. It would, therefore, be lost labour to introduce the water on the first high tide produced by such winds, when the water would probably be weakened by the succeeding rains. The best time, in such cases, of introducing the water would be on the first prospect of a change; easterly winds being generally succeeded by a north or south wester.
[Page 34] Suppose then, the water to be introduced at such a time; the quantity thereof must be determined,
1st, By the deficiency of water in the reservoirs.
2dly, By the probability of the continuance of fine weather.
If the reservoirs are nearly empty, (which is not likely after a series of bad weather, though they may have become so in consequence of intermitting rains having prevented a supply from the pond,) and there is to be expected a continuance of fine weather, a larger quantity must be admitted; although even this must be regulated by the consideration of the approaching spring or neap tides.
After the water is admitted, the depth of which in the pond should not in general exceed six inches; it should be suffered to remain there till the next appearance of rain, (unless a portion of it be wanted for the immediate supply of the works) when, if the weather has continued fine for some days, it will have been considerably strengthened.
[Page 35] It will readily occur that after a succession of fine weather, the contents of the reservoirs will be considerably lessened; of course, on the apparent approach of rain, after such a season, they will be capable of receiving a great supply. This is, therefore, the important time to secure in the lower reservoir as much of the strengthened water from the pond as possible. These occasions should be carefully watched; and, the power of the lower pump being calculated, proper time should be allowed for filling the lower reservoir before the rain comes on.
The average quantity of salt contained in sea water is one bushel in thirty.
Though the natural evaporation in this country is only about fifty six inches in the year; yet the evaporation during a week of fine weather will frequently exceed three inches.
Suppose then water which originally contained one bushel of salt in thirty, to have been admitted into the pond to the depth of six inches, and three inches thereof to have been evaporated during a fine week; fifteen bushels of the remaining quantity of water will yield one bushel of salt. A [Page 36] circumstance [...] like this will double the produce of the vats, without increasing the expense of working them.
These are advantages which it must be confessed do not occur frequently in this country; but when they do occur they are great, and if properly attended to, will considerably contribute to the success of such undertakings.
A series of fine weather for three or four weeks, may reasonably be expected three or four times every year. It is proper always to be prepared for such occasions, and when they do happen they will amply repay the trouble of preparing for them.
This pond has a sluice by which it empties itself into the river at low water, after rain or when occasion requires.
In winter, this pond will be still more advantageous, and to it a more regular attention is then necessary than in summer.
In the beginning of winter a severe frost frequently operates during the night, and a proportionable thaw during the day.
When such weather is expected, the use made of the pond should be this,
[Page 37] Only a small depth of water should be admitted, proceeding accordingly to the supposed strength of the succeeding frost, from two or three inches, upwards. The contents of the pond being exposed to the frost during the night, the part found condensed in the morning will consist alone of fresh particles, the remaining fluid containing all the Salt originally contained by the whole.—This then, or so much of it as necessary, must be pump'd into the lower reservoir before the thaw begins; and the sluice opened immediately to let off what remains in the pond, as the thaw renders it fluid. In the evening, if circumstances permit, a quantity of sea water must be admitted by the other sluice, as before, and so on.
As the winter advances, the quantity of water admitted into the pond must be greater; as the frost will have the greater effect—but it is impossible to give rules for the work of every day throughout the year; the operator must reflect, judge, and act accordingly.
But when the winter is well set in, the attention to the pond will be less varying and troublesome, but more requisite and profitable.
What is generally called the setting in of frost, is less a matter of doubt than the expectation of fine [Page 38] weather in summer, and may, therefore, with greater confidence be relied on.
Attention to the admission of water at high tides, is not so necessary in winter as in summer; as the frost operates with greater force on the weaker water; therefore,
On the approach of a severe frost, it would be (generally considered) adviseable to let into the pond as much water as it will contain, which should not exceed two feet in depth, and remove the water from under the accumulating ice, only as it may be immediately wanted; as it will become stronger and stronger every day during the continuance of the frost.—Upon the commencement of the breaking up of the frost, all diligence must be applied to the securing of the strengthened water in the lower reservoir, which will serve for use during the succeeding thaw while the ice is dissolving in the pond and retiring through the sluice into the river.
If the frost should at any time be so severe, as to leave only a small quantity of water uncongealed, more must be admitted from the river, and a large hole made in the ice near the admitting sluice to suffer the fresh supply to run under it.
[Page 39] It would greatly facilitate the security of any quantity of water strengthened by the pond in summer or winter, to have an additional reservoir, (if circumstances would admit of it) sunk below the level of the bottom of the pond, so that on the approach of rain in summer, or thaw in winter, the strengthened water might, by a capacious sluice, be at once let into it. This indeed would be necessary where extensive works required a large pond, as it would be difficult or at least expensive, to raise a very great body of water between the appearance of approaching rain, and its arrival, whereas, by introducing this last mentioned reservoir of sufficient capacity, the whole might be at once secured in a few minutes; nor would the raising the water therefrom, produce an additional expense to the yearly establishment, as the man and horse, or men and horses, might be employed during wet weather, (when they could do nothing at the vats), in filling the other reservoirs therefrom.
It would also be the means of affording the man more leisure to cover the crystallizing canal, and prepare the rest of the works against the arrival of rain, as will be hereafter explained.
[Page 40] Having now observed every thing that I believe to be necessary to convey a just idea of the proper management of the pond, I shall proceed to the consideration of the other parts of the works.
THE PUMPS
Come next in course. These should be worked by a horse, under cover, as they will be generally used during moist or wet weather when nothing can be done at the vats. No particular remarks appear necessary on this subject, excepting that the height of the water raised by the lower one should be as little as possible, that the greater quantity may be secured in a short time; the raising the water from the lower to the upper reservoir, being a work of more leisure, the height of the pump for this purpose may be greater without inconvenience.
THE RESERVOIRS.
Respecting the Reservoirs few observations are necessary. The principal care requisite is to keep them properly supplied. Some evaporation may be expected from them, and in winter considerable additional advantages may be derived [Page 41] from them by frost—by removing the ice formed on the surface of the water. These reservoirs being constantly covered, nothing need be observed on them respecting rain, from which the water contained in them is secured.
We now come to the vats, the principal object in the works.
THE VATS.
I have before mentioned that sand is used as the principal instrument of evaporation, and given the reasons therefor. I shall now consider its effects.
Water when imbibed by sand, and the sand so moistened spread regularly over a level plane and occasionally raked, will evaporate at least four times as fast as it will in a fluid state exposed to the same sun and air.
Sand will absorb and retain about one third of its bulk of water, and will, on the average, if properly attended to, evaporate the same in four and twenty hours.
[Page 42] Suppose then ten vats, of sufficient capacity to contain each, when spread regularly over its bottom, 300 bushels of sand.
Suppose each of these vats to absorb, and evaporate daily 100 bushels of water. Suppose each 100 bushels of water to contain 4 bushels of salt.
After six successive wettings and dryings the sand in each vat will contain 24 bushels of salt.
On the seventh day, let into vat No. 1, 1,100 bushels of salt water, containing at 4 bushels per hundred, 44 bushels of salt. This water, being stirred about with the sand, will dissolve the salt found with the sand, in addition to what it brought with it, and having dissolved it, will then contain 68 bushels, or about 6 per hundred.
On letting the water into the 2d vat, the sand in the 1st vat will retain thereof 100 bushels, and with them the quantity of salt contained in those 100 bushels, viz. 6 bushels.
The 1st vat will then stand thus;
—Sand containing 6 bushels of salt.
[Page 43] 1000 Bushels of water, containing 62 of salt, will run off into the 2d vat, where they meet 24 bushels more of salt; which having dissolved, the water stands thus—1000 bushels containing 86 of salt or about * 8½ per hundred; 900 of which being let off into the 3d vat,
The second will stand thus,
—Sand containing 8½ bushels of salt.
900 Bushels of water, containing 76½ of salt, being let into the 3d vat, meet there 24 more of salt; which having dissolved, the water stands thus, 900 bushels containing 100½ of salt or about 11 per hundred; 800 of which being let off into the 4th vat,
The 3d will stand thus,
—Sand containing 11 bushels of salt.
800 Bushels of water, containing 89 of salt, being let into the 4th vat, meet there 24 more of salt; which having dissolved, the water stands thus, 800 bushels containing 113 of salt, or 14⅛ per hundred; 700 of which being let off into the 5th vat,
[Page 44] The 4th will stand thus,
—Sand containing 14⅛ bushels of salt.
700 Bushels of water containing 99 of salt, let into the 5th vat, meet there 24 more of salt, which having dissolved, the water stands thus; 700 bushels containing 123 of salt, or about 17½ per hundred; 600 of which, being let into the 6th vat,
The 5th will stand thus,
—Sand containing 17½ bushels of salt.
600 Bushels of water, containing 105 of salt, let into the 6th vat, meet there 24 more of salt; which having dissolved, the water stands thus;—600 bushels containing 129 of salt, or 21½ per hundred; 500 of which being let off into the 7th vat,
The 6th will stand thus,
—Sand containing 21½ bushels of salt.
500 Bushels of water, containing 107½ bushels of salt, let into the 7th vat, meet there 24 more of salt; which having dissolved, the water stands thus; 500 bushels containing 131½ of salt, or 26 per hundred; 400 of which being let off into the 8th vat.
[Page 45] The 7th will stand thus;
—Sand containing 26 bushels of salt.
400 Bushels of water, containing 104 of salt, let into the 8th vat, meet there 24 more of salt, which having dissolved, the water stands thus; 400 bushels containing 128 of salt, or 32 per hundred; 300 of which being let off into the 9th vat,
The 8th will stand thus;
—Sand containing 32 bushels of salt.
300 Bushels of water, containing 96 of salt being let into the 9th vat, meet there 24 more of salt as in the other vats, but, being incapable of dissolving more than it already contains, * the 200 bushels when let off into the 10th vat will leave the 9th thus:
—Sand containing 56 bushels of salt.
200 bushels of water, containing 64 of salt, let into the tenth vat meet there 24 more of salt; but [Page 46] being incapable of dissolving more than it already contains, 100 bushels when let off into the reservoir will leave the sand in the tenth vat as follows:
—Sand containing 56 bushels of salt.
100 Bushels of brine let off from the 10th vat into the reservoir, after depositing its impurities will be ready on the first fine weather to be exposed for crystallization, and will yield 32 bushels of salt, or thereabout.
It will readily occur to every one, from the quantity of salt left in the vats, that a much larger quantity of water might have been saturated; but it is much better to leave the sand richly impregnated, than to impoverish it by removing all the salt, or as much as possible at once. Reasons shall hereafter be assigned for this remark.
32 Bushels of salt, (or 100 bushels of brine containing that quantity) have then been procured by this process on the seventh day.
The fresh particles of the water left with the sand, having evaporated, and the sand having become dry, the same process should be continued [Page 47] on the eighth day, when the same quantity of saturated brine will be yielded as before, and the vats on the 6th, 7th, and 8th days, will have been left as in the following table.
| Vat. | 6th Day. | 7th Day. | 8th Day. | ||
| No. | 1 Sand contg. | Bush. of Salt. | 24 | 6 | 4½ |
| 2 Sand contg. | 24 | 8½ | 5½ | ||
| 3 Sand contg. | 24 | 11 | 7 | ||
| 4 Sand contg. | 24 | 14 | 8½ | ||
| 5 Sand contg. | 24 | 17½ | 11 | ||
| 6 Sand contg. | 24 | 21½ | 14½ | ||
| 7 Sand contg. | 24 | 26 | 19½ | ||
| 8 Sand contg. | 24 | 32 | 26½ | ||
| 9 Sand contg. | 24 | 56 | 75½ | ||
| 10 Sand contg. | 24 | 56 | 88 | ||
| Total. | 240 | 248½ | 260½ |
It is unnecessary to pursue these calculations further; what has been done is sufficient to show the progress of saturation, and the manner in which the end contemplated is effected.
The process is regularly continued during fine weather, and every time the sand dries, the fame quantity of brine may be procured, and the vats will be left more and more impregnated with salt.
The principle advantages arising from leaving the vats strongly impregnated with salt are the following.
[Page 48] It will sometimes happen that the sand may not be sufficiently dry, when it will be necessary on many accounts to wash the vats; less water will of course in that case be retained by the sand in each vat, and of course the greater quantity remain in the tenth—if, therefore, there was only salt enough left with the sand to saturate one hundred bushels of water, 150, or 200 bushels being left to be drawn off into the reservoir, would be unfit for immediate use, and if drawn off into the reservoir would weaken the brine before contained therein, and thereby probably put a stop to the regular process of crystallization.
Again, on the approach of rain, the vats should always be washed, that the sand may be left fully saturated with salt water, and with a smooth surface; that the rain, when it falls, may remain on the surface unmixed with the sand or salt water; and on the return of fine weather quietly be drawn off through a hole in the bottom of each vat. Now, the sand being left strongly impregnated with salt, will always afford sufficient to saturate the extraordinary quantity of water used for this purpose, which, however should never be more than necessary to pass through all the vats and leave the sand a smooth, wet and compact mass; which being done, the rain will fall on the [Page 49] sand without doing any material injury, and may be let off from each vat on the return of fine weather as fresh, or very nearly so, as it fell.
It would be generally prudent, during the summer, to wash the sand in the evening, when the weather is calm or doubtful, leaving the raking of it till the morning.
This answers two purposes, it leaves the sand prepared against accidental rains during the night, and the vats are the sooner ready in the morning for evaporation.
But, when the night is expected to be fine and evaporating, the raking should not be postponed unless the washing is postponed also.
During dry windy weather, and particularly when it happens during the night, when the machines cannot so easily be watched, the sand should not be suffered to dry as in calm hot weather, but should be kept regularly moistened: this may be done by permitting a stream of water proportionate to the evaporation to run constantly from the reservoir, draining from the first vat into the second, and so on: this not only prevents [Page 50] the sand from being blown away, but forwards evaporation very considerably.
Care must in general be taken to lose no advantages of fine weather, by doing that kind of work in the middle of the day, such as wetting the sand &c. during the most powerful evaporation, which may as well be done in the morning or evening when the evaporation is less.
In spite, however, of the greatest care and attention, accidental circumstances may sometimes bring into the tenth vat, a quantity of water not fully saturated; this should by no means be admitted to the reservoir (H) To provide against difficulties of this nature it would be proper to have a spout running under the vats to convey the water on such occasions back to the lower reservoir (C). This would be attended with no other disadvantage, but that of raising such a quantity of water a second time to the upper reservoir (E).
It is to be observed, that all the foregoing calculations have been made on a supposition, that the water issues from the upper reservoir (E) containing four bushels of salt in one hundred of water, or one bushel in twenty five. The pond [Page 51] and lower reservoir being well attended to, it will never contain less, but frequently and generally more.
For instance. Suppose 6 inches of water to have been admitted into the pond, and during a series of fine weather three inches thereof to have been evaporated; if the water originally contained one bushel of salt in thirty, it will then contain one bushel in fifteen.
If two inches only should have been evaporated, it will contain one in twenty, and so on.
Water, so strengthened, being secured in the lower reservoir, will considerably increase the profits of the works; and as attention to the pond is attended with very little difficulty, and no expense, (circumspection being the principal requisite while the water is strengthening, and care to secure a sufficient quantity when strengthened,) it must be owing to bad management alone, if the water, by the time it arrives in the upper reservoir, does not contain more than one bushel in twenty five on the average throughout the year.
[Page 52] The vats in winter are in general more profitable in producing brine than in summer, but require a different process. The business then is this.
In the beginning of winter, on the evening preceding an expected frost, after having washed the sand, and extracted all the salt possible; a quantity of water must be let into each vat, proportionate to the expected density of the frost, and there suffered to remain all night; in the morning, before it begins to thaw, the strengthened water must be drawn off and returned by the spout under the vats to the lower reservoir: as it begins to thaw, the cocks leading from one vat to the other must be stopped, and the plug in the bottom of each vat opened, to let off the condensed part as it becomes fluid. All being gone the plug must be stopped if the weather is fine, the sand raked and exposed to evaporation.
But, as the winter advances, this daily trouble will not be requisite; for, when it ceases to thaw during the day, the water may be continued in the vats, and exposed to the frost till it is nearly saturated; when it must be drawn off; and if the frost continues, the ice removed, and a fresh quantity of water exposed for condensation; or [Page 53] if a thaw attended with rain is expected, the trouble of removing the ice may be avoided by opening the plug, and letting it run out as dissolved.
Calculation at the time of operation must determine the propriety of adopting either of these expedients; I shall only add that by a careful attendance to the pond, reservoirs, and vats, during the winter, an immense quantity of strong salt water may be secured ready for the operation of spring, and which will treble the produce of the sand, when by the retiring of the frost it is at liberty to operate.
With respect to the reservoir for the brine, little is necessary to be observed. No brine should be received in it till perfectly saturated, nor withdrawn from it, till perfectly settled and clear.
The crystallizing canal (or canals,) should be about a foot deep, with sliding covers, which may with ease be drawn off or on as the weather requires. These covers should consist of light pine frames with painted canvas tightly stretched over them. The brine, when let into this canal will begin to crystallize in a few hours, in small white cubes, which will increase in size so long as they are suffered to remain undisturbed.
[Page 54] When the salt is to be taken out, baskets should be placed, (at regular distances), so as to drain into the canal: the man then goes into the canal and shovels the salt into these baskets, where having remained about half an hour, it becomes sufficiently dry for storing; the man then attaches the horse to the cart, and driving along the side of the canal fills the cart with the salt, and takes it to the warehouse; having taken out as much as necessary, he slides on the covers, and leaves it till the morning, when, if the remaining fluid contains no more marine salt, it is let off, unless wanted for the purpose of making Epsom or Glauber salts, which with very little trouble it would produce in abundance.
I have now entered into a complete description of every part of the works, and the method of managing them; from which it must appear that after such machinery is erected, the business may be carried on at a very small expense. I have already ventured to observe that one man and one horse could, without any other expence, from works sufficiently capacious, make one hundred bushels per day on the average throughout the year; and I believe it to be the fact.
It is unnecessary to make minute calculations on the expense of erecting such works, as the [Page 55] prices of timber, boards, labour, &c. vary according to situation. Works, in any situation, where the above articles were easily procurable, which would produce 100 bushels of salt per day on the average throughout the year or 36,500 bushels per year might, I am sure, be erected for less than 15,000 dollars; and smaller or larger works in proportion.
Miscellaneous Observations.
MUCH expence may be saved in the erection of these works, by chusing a convenient spot for the purpose; and much may be added to the produce, by adopting a situation, where the soil and air are generally dry, and not subject to fogs, mists or damp exhalations.
There are many situations on the banks of salt water rivers, formerly the habitation of Indians, where the upper stratum of the soil consists chiefly of oyster and other fish shells; such a situation, if suitable in other respects, would be peculiarly advantageous, not only from its natural warmth, but from its porosity suffering the rains as they fall to sink beyond the reach of evaporation, and leaving the surface dry, thereby preventing that saturation, or rather that approach to saturation of the air, which in calm hot weather generally succeeds heavy rains, in situations where the soil being less porous suffers the water to stagnate on its surface.
[Page 57] Air is always in search of water, and where the soil, powerfully acted upon by the sun, yields it freely, will soon saturate itself▪ hence that vibratory motion in the air often visible in calm hot weather, when the heated soil exhales more moisture than the stagnating air will immediately dissolve.
Air, though in a dead calm it may be said to have no positive motion, has yet a relative one, that is, though in a large body it may not be moving from one place to another, yet is there constantly a circulating motion of its particles within itself; like the circulation of the blood through the body of an animal though the animal itself be at rest.
Now suppose a large body of air positively stationary over a tract of ground remaining a long time wet after heavy rains, (on which such works are erected) and yielding freely its moisture to the air; does it not necessarily follow that that air fed equally from every part of the land, must be soon saturated with water, and remain a dead, though perhaps invisible mist, having no evaporating power, till the whole body be driven away by a succeeding current?
Suppose, on the other hand, a similar body of [Page 58] air to remain stationary, over a dry tract of ground, on which such works are erected, yielding only scanty exhalations; will it not naturally occur that the air will seek for food where only it can be supplied, and attacking the vats for moisture, which sand naturally repels, feed itself from them? A number of particles being fed, relative motion immediately succeeds, from two causes; increased gravity of the particles, and the changing angles of refraction of the solar rays; partial motion being obtained, a general (relative) motion will soon take place; for, the solution of water in air is similar to the solution of salt in water; impregnate a part, and that impregnation will soon be dispersed throughout the whole. If this hypothesis be just, the advantages to be derived from fixing the works on a dry soil must be very great, by forcing a large body of air in calm weather to feed itself from the moisture of the vats, when it would otherwise be saturated by the surrounding exhalations.
There are some places where natural ponds are formed near the water, which with a little expense, may be adapted to the purpose desired in these works.
By chusing a situation for the vats where the [Page 59] ground has a declivity of 18 or 20 feet, the expense of raising the reservoir and vats may be avoided.
It is not very essential to have them close together; of course, the more compact works of this nature are, the better; but, if the ground would not afford a sufficient descent for the vats if close together, they may be placed at the distance necessary for that advantage, and communicate with each other by means of a spout. Some little inconveniences may occur from an adoption of this plan, but they may be easily obviated or counterbalanced by a judicious manager.
The bottoms of the water reservoirs, vats, and crystallizing canal, may be of pine boards, if good: The lining of the reservoir for the brine, should be made entirely of two or three inch plank well caulked and pitched: the bottom of the crystallizing canal should be pitched all over: this will accelerate the crystallization, and prevent the brine from soaking through the bottom.
The sides of the vats and crystallizing canal should be made of one plank in depth cut feather edged, the lower edge being about four inches thick, the upper, one.
[Page 60] If the vats are built in the shape of a rectangular paralellogram; care should be taken to place the sides towards the south, letting the vats extend east and west; otherwise, a great part of them will be shaded from the morning and evening sun.
In planning the vats, it appears best to have them long and narrow, that the boards may be laid crossways; the breadth of the vats being determined by the length of the boards, to prevent waste and buttings: by having them in this manner, the boards when jointed may be wedged up very tight, and no caulking will be necessary. Besides, if the vats are worked by a horse, this plan obviates three great disadvantages which would otherwise occur; frequent turnings, walking constantly on one board, and treading between the joice.
I shall now dismiss the subject with a firm hope and belief that some time or other I shall have it in my power to say, "my labour has not been in vain."