# Enclosure: Description of the Scale Accompanying Dycases Hydrometer, [18 December 1790]

# [Enclosure]

Description of the Scale accompanying Dycases Hydrometer3

One side of it represents the different degrees of strength of Liquors from water to proof, of this no use will be made in the execution of the law.

The other side which is that to be made use of represents the different degrees of Strength from 20 ⅌ Cent below proof to 69. above proof or Alcohol.

On this side towards the left is a plain Space with a flower de liece, (Figure thus ) in the center of that space which is marked A. The better to distinguish it, on the left hand and upper edge of the Slider (or moveable piece in the middle), are graduations from thirty to Eighty; which are intended to correspond with the same degrees of Fahrenheits Thermometer, the other sizses of graduations and numbers of the Slider from 100. to 370 are intended to correspond with the sum of some one of the numbers of the weights in the Box, &c. some one of the divissions of the Stem of the Hydrometer, as will be hereafter Explained, the outside numbers (or those nearest the edge) on the Scale both above and below the Slider from 20. to proof, and from proof to 76, designates the number of gallons of Water which added to any given Strength of Spirits will bring it to proof, if more than proof, or if only proof to 20. ⅌ cent below it.

The inner numbers on the body of the Scale above and below the Slider, and the graduations corresponding with them, express the different degrees of the Strength of spirits from 20 ⅌ cent below proof to 69 ⅌ cent above proof, which amounts to Alcohol.

Proof is represented by the line which runs through a certainfigure thus with the word proof over it. The graduations on the left of it on the upper edge express, so many degrees ⅌ cent below proof, from 1. to 20. those on the right on the upper side, and those below express the degrees ⅌ cent above proof. from 1. to 69. It will be observed, that the numbers 190. and 200. are twice repeated, once on the upper and once on the lower part of the Slider, and it will also be observed that the number 20 on the body of the Scale is likewise twice repeated once above and once below the Slider, and it will be found, by tryals that the numbers so repeated correspond with the same numbers above and below, which are repeated on the Scale, whence it will be the same thing, which of them are made use of in the opperation.

The Hydrometer is the brass Instrument in the Box, graduated or divided on the upper stem from one to 10, the round pieces of Brass in the box in a Series from 1 to 350 serve as weights, some one of which fixed upon the stem will sink the Hydrometer in the Liquor to some divission on the stem, or at least till the bubble is below the upper surface of the liquor, what particular weight will do this depends on the Strength of the liquor.

The Process in the use of this Hydrometer is as follows. First immerse one of Fahrenheits Thermometers in long enough to express its true temperature; which in respect to the smallest kind will be very short. This being done, find the degree on the Slider which corresponds with that of the temperature of the liquor expressed by the Thermometer, then place the Slider, as that this degree may exactly coincide with the Stem of the Flower de liece.

Next immerse the Hydrometer in the Liquor, and place upon the upper part of the Stem that precise weight, which will Sink the Bulb, below the Surface of the liquor to some one of the divisions on the stem; if the weight be too heavy it will intirely sink the Hydrometer stem and all, if it be too light some part of the bulb however small, will remain above the surface of the liquor, in neither case will the weight be the right one, when the proper weight is found and applied, you add the number on the weight to the number of the division on the stem, marked or designated by the surface of the liquor. The sum of these numbers is now to be looked for on the Slider, and immediately above or below it on the Scale is found the degree ⅌ cent which the liquor is above or below proof.

An example may make this plainer. Suppose the degree of the Temperature found by the Thermometer to be 40. Place then 40 the corresponding graduation on the left of the Slider in coincidence with the stem of the flower de liece.

Suppose also that the number of the weight which will sink the Hydrometer to some division of the stem is 150. and that the number of that division is 2. These two numbers added together make 152. Look for the last number on the Slider, and directly above it on the Scale you find the number 10 which denotes the liquor is ten ⅌ cent above proof.

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