THE PRACTICAL GAUGER.
IT would be very convenient, that every Gauger were well acquainted with the Art of Decimal Arithmetick; but it is necessary that he be so well seen in Vulgar, as to be able to add, subtract, multiply, and divide any whole Numbers.
It is also necessary, that he understand the three sorts of Quantity, [Page 2] viz. a Line, a Superficies, and a Solid.
A Line hath length, but no breadth.
A Superficies hath length and breadth, but no depth.
A Solid hath length, breadth, and depth.
Moreover there is no kind of Quantity but is commensurable by some Common Measure thereto assign'd, as a Line by a Line of Inches, Feet, Poles, Furlongs, &c. and a Superficies by a Superficies, as the Square Inch, &c. and also a Solid by a Solid: So when it is known how many Inches, Poles, or Furlongs is contained in any Line, the length of that Line is said to be known; and when it is known how many square Inches, square Feet, or square Perches are contained within any Superficies, the Content or Area of that Superficies is said to be known; and also when it is known how many solid Inches are contained in any [Page 3] Solid, the Content of that Solid is known.
To find the Content of a Back in the form of a Square or Parallelogram.
The Rule is:
Multiply the length by the breadth, and the Product divide by 282 (the number of solid Inches contained in the Ale Gallon) and the Quotient is the Ale Gallons contained upon one Inch in depth of that Back or Tun.
[Page 4] [...]
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[Page 5]One contains 10 Gallons, and 205/282 parts of a Gallon; the other 21 Gallons and 128/282 of a Gallon. To reduce which Fraction into Pints, you need only multiply the Remainder or Numerator by 8, and divide by the old Divisor, and the Quote will be the Pints contained in that Fraction.
To find the Area or Content of one Inch of a Back or Tun, in the form of a Triangle, in Ale Gallons:
The Rule is:
Multiply the Line a c ( viz. the Line falling perpendicularly from any Angle on its opposite Base) by half the Line b c d, here the Base, and the Product divide by 282, the Quotient will be the Ale Gallons contained in one Inch of depth upon that Triangle.
[Page 6] Example.
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There is contain'd in the first Inch of this Back or Tun 63 Ale Gallons, 6 Pints, and above an half.
[Page 7]But admitting the Back or Tun be of an irregular Form, divide it into Triangles, and let fall Perpendiculars in each, and find their several Area's, as in the last Example, then add them together, and you have the Content or Area of the whole Figure.
Example.
First I find the Triangle abe.
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[Page 8]Now in the other two Triangles, the two Perpendiculars falling upon one common Base, I multiply the Sum of the Perpendiculars by half the Base, and that Product is the Area or Content of both Triangles.
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So doth one Inch of this Back or Tun appear to contain of Ale Measure, [Page 9] 9 Barrels, 3 Firkins, and 3 Gallons.
Here Note, That formerly the Ale Gallon was accompted to contain 288 ¼ Cube Inches; but by the care and pains of my good Friend, Mr. Nicholas Gunton, the just quantity of the Quart, remaining in the hands of the Chamberlains of His Majesties Exchequer, appears to be 70 ½, as some of late have found to their no small cost. And I am of opinion, that if the Wine Gallon were carefully examined, it would prove to contain less than it is commonly holden to do, by so much as would improve the Revenue of the Crown some thousands per annum.
Now having shewed thee how to find the superficial Quantity of any Figure enclosed or bounded by Right Lines, if the Dimensions be alike above and below, multiply the Area by the Depth and you have the Content [Page 10] of the whole; or by any part, and you will find thereby the Solidity of that part.
But if the Dimensions above and below be unequal, take your Dimensions or cross Diameters at every Foot or half Foot, and so find the Solidity.
Of a Circle.
A Circle is a Figure contained or bounded by one Line, which is called the Circumference, as the Line abgd.
[Page 11]Within which Line there is a Point, from whence all Lines drawn from the Circumference are equal: And that Point is called the Center, as the Point c: And through which all Right Lines drawn from one side of the Circumference to the other divide the Circle into two equal parts, and that Line is called the Diameter, as the Line a c b; and the two parts of the Circle, divided by the Diameter, are called Semi [...]circles, as the part a c b g or a c b d.
And although there is not yet found any true proportion between a Square and a Circle, (a Square Inch being our Common Measure) yet is there an Approximation found by Vanculen, which comes almost infinitely near the truth, being as Unity to 3.14159 &c. to the Square of the Semi-diameter. But the old Proportion comes near enough for common practice, viz. As 14 to 11, so is the Square of the Diameter to the Area in Square Inches, &c.
[Page 12] Example.
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Which Area in Square Inches divided by 282 quote the Ale Gallons contained in one Inch of depth in that Circle, or by 231 the Wine Gallons.
[Page 13] Example.
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But I would advise my young Gauger not to trouble himself with the [Page 14] Inches, his business being to find the Gallons the shortest way he can: In order whereunto, let him observe the following Rule.
Having the Diameter of a Circle in Inches, to find the Area or Content in Ale or Wine Gallons.
The Rule.
Square the Diameter ( viz. multiply it by it self) and that Square or Product divide by 359 for Ale, and 294 for Wine, and the Quotes will be the Ale or Wine Gallons respectively, that shall be contain'd in a Circle of that Diameter, and one Inch in depth.
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[Page 15] [...]
If the Tun be in form of a Cylinder, viz. like the Rolling-stone of a Garden, the Circles above and below of equal Diameters, then to find the Content of that Tun, or any part thereof, you need only find the Area of the Circle, and multiply by the whole Depth, or such part as you desire, and the Product will be the Solidity of the whole, or part, respectively.
[Page 16] Diameter ab or cd = 80 Inches, the Area before found to be 17 gallons 6 pints, and the Depth = 40 Inches: To find the Content.
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The Content of this Tun in Beer Measure.
But if your round Tun have unequal Dimensions above and below, it is then taken to be the part of a Cone or round Pyramid, having the top cut off as the following Diagram; the whole Cone = abcdefg, the part or Frustum = abcdeg.
Having the two Diameters and Depth of the Tun, to produce the whole Cone the Rule is by Proportion thus:
As the Semidifference of Diameters is to half the Diameter at the Base: So is the height of the Frustum to the Cones whole Axis.
Admit ab 80, cd 140, eg 50, then is the Difference 60, half the Base 70.
[Page 18] Example.
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Having all these Dimensions, the Content of the Tun is not hard to be found.
For if you find the Area of the Base, and multiply that Area by ⅓ of the Altitude, or ⅓ of the Area by the whole Altitude, the Product is the Solidity of the whole Cone. Then having found the whole Cone, find also the lesser Cone, and subduct that from the greater, the Remainder will be the Content of the Frustum.
Or if you would find the Content of the Frustum, without producing the whole Cone,
The Rule is:
Multiply the Sum of the two Diameters by it self, then multiply the two Diameters by each other, subduct the lesser Product from the greater, and the Remainder multiply by the depth, the last Product divide by 1077, and the Quote is the Ale Gallons contained in that Tun.
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[Page 20] [...]
The Content appears to be 1727 Ale Gallons, or 47 Barrels, 3 Firkins, 8 Gallons.
If it be desired in Feet or Inches, you may find all the Differences of the Diameters, at every Foot, half Foot, or Inch, by this Proportion:
As the whole Depth, is to the Difference of Diameters: So is any part of the Depth, to its respective difference of Diameter.
Then by Addition or Subduction, you have the Diameters all the way upward or downward.
[Page 21]Or, if you please, you may take the Diameters actually, in the midst of every Foot or half Foot, and seek its Area in the Table of Area's hereto annexed, which Area multiplied by the Foot or half Foot gives the Solidity accordingly, without any sensible errour. This way I would oblige the young Gauger to, if he be not ready at Proportion.
Example.
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[Page 22]All these Mean Diameters cut this Tun into so many Cylinders.
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Now having the Area of each Circle, which is an Arithmetical Mean of the half Foot, multiply this Area by 6, and the Product is the Solidity of that half Foot.
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This Tun cast up by the Rule, pag. 19.
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Whereby appears not a Gallon difference.
If the Conjugate or Cross Diameters above and below are not equal, then do Geometricians call that Tun Eliptical; to reduce which to a Circle, there ought to be a Geometrical Mean taken, but the common practice [Page 24] is to add them together, and take the half, which if the Diameters differ not much, the errour is the less.
Coppers are commonly taken at every 6 Inches, as that Tun in pag. 21.
To find the Content of a Coppers Crown, take this Rule:
Square the Diameter at the Base, to this add 4/3 of the Square of the Crowns Altitude, the Sum multiply by the Altitude, the last Product divide by 718, the Quote is the Ale Gallons contained in that Crown.
To find the Content of the Mash Tun, in Quarters, Bushels, and Gallons, there can be no certain Rule in taking the Depth of the Goods, by reason of the difference in the goodness of Mault, some spending it self much more in the wetting than other; yet that considered, there may be some estimate given thereto, whereby a very considerable fraud may be discovered.
[Page 25]In a square Mash Tun, divide the Product of the Length and Breadth by 227 for indifferent, or by 200 for the finest, and the Product will be the Gallons wetted; and for round Mash Tuns, let your Divisors be 288 or 260, respectively.
For Cask-Gauging, wholly full, I have given many Precepts and Examples in a Treatise called The Merchants Companion, Printed about a year since; but that the Reader may not be left here wholly without, take the following Rule, which considers the Cask as the Frustum of a Spheroid, that being the most general form.
To find the Content of a Cask in Ale or Wine Gallons.
The Rule.
To the doubled Square of the Boung Diameter add the Square of the Head Diameter, and that Sum [Page 26] multiply by the Casks Length, the last Product divide by 1077, and the Quote is the Ale Gallons, or by 882 quotes the Wine Gallons contained in that Cask.
Example.
[...] [Page 27] [...] The Content of this Cask is 73 Ale Gallons, 2 Pints, and almost an half.
Or, by the Table of Area's, thus:
To twice the Area of the Boung Circle in Gallons and parts add the [Page 28] Area of the Head Circle, the Sum of these multiply tby ⅓ of the Casks Length, and the Product is the Content in Gallons and parts, as in the former Example.
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Which Fraction being reduced is 2 Pints and better, as was before found.