144 ALCOHOL—Field’s Alcoholometer.

Althougpoint of \neutral salf.ict to thein spiritucBrossap.dthe "boilimportion toirrespecth

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li it had long been known that the boilingrater was raised by the solution in it ofts and other bodies, the application of thisdetermination of the quantity of alcohol)us liquors was reserved for the AbbeVidal, of Toulon , who ascertained thatpoint of such liquors was in direct pro-the quantity of alcohol they contained,e of any amount of saline ingredientspresent in them.Fi s- 61 - When such salts are

added to dilute alco-hol as abstract a por-ESjEuj tion of the water, the

J ]>»■» u boiling point of the

'»■£. solution is lowered,

0 . '

T 1instead of the reverse

; : being the case.

:: i: 1 '! This principle also

-t- F ’■ formed the basis of

— - - as

3E: “ Field’s aleoholo-

L meter, for the de-

rt termination of the

= amount of spirit in

if every description of

:E if foil alcoholic liquor at any

f P® J period after fermen-

tation, for which heJ _ J RRM obtained a pateht in

!/i ;;j! IL 1847. It consisted

"liV 11 1 originally of a spirit

! J | ill 1 lamp, surmounted by

il‘ 11 HP* a boiler containing

"f'MNH the liquid to l 5 ® ex_

H amined, and a large

H cylindrical glass bulb

B : | H containing mercury,

M ■ and having an upright

11 1 jfl stem, whose calibre

| | BHlIfc--: was such as to allow

1 | i|jaEjfei the expansion of the

mercury to elevate asmall glass float whichBffl KM rested on its surface.

iSn J5ji h |fl§ : : This float was con-

III ill dll ■ — necte d by a threadjlJJJI with a similar bead,

ini M ito. which hung in the~i i' T | open air; the thread

a .1 passed over a pulley

| j ■Hpp which, turning with

1 j 1 j iljllpfe^-- the motion of the

^-beads, caused the in-

ve along the circular graduated scale. Thist was much improved by Ure, who intro-tead of the cylindrical bulb and beads, ater attached to a graduated scale. Fig. 51improved instrument,spirit lamp, surrounded by an outer coat-ling cold water for keeping the lamp cool,ny successive experiments be required; ber, which fits into the cage, C, in the casep; a damper, tf. regulates the heat of the

lamp; E is the thermometer, which has a very smallbore. The bottom of the scale on the ebullitionthermometer is marked P, for proof, on the leftside, and 100—proof spirit—on the right side. Itcorresponds with 178-G Fahr. nearly, or the boilingpoint of alcohol, spec. grav. ‘920.

From the mean of a great number of experiments,

Ure drew up the following table, which shows theboiling point of alcohol of various specific gravities:—

Temperature Fahr. Specific gravity.

178- 5 . 0-9200 . — Proof.

179- 75 . 0-9321 . 10 Under proof.

180- 4 . 0-94*20 . 20 “

182- 01. 0-9516 . 30 “

183- 40 . 0-960 . 40

185-6 . 0-9665 . 50 •*

189-0 . 0-9729 . 60 “

191-8 . 0-9786 . 70 “

196-4 . 0-9850 . 80 “

202-0 . 0-992 . 90 “

When the spirit is above proof, the variation ofits boiling point is so small that a strictly accurateresult cannot be obtained: proof spirit, or spiritapproaching to that strength, is more accuratelytested by diluting it with its own bulk of waterbefore ascertaining the strength, and then doublingthe result. Another source of error pointed out byUre, is the elevation of the boiling point when theliquor is kept heated for any length of time ; this is,however, obviated by the addition of common saltto the solution in the boiler of the apparatus. Inorder to correct the difference arising from a higheror lower pressure of the atmosphere, distilled watershould be boiled in the apparatus, and the tempera-ture noted; for the boiling point of the alcoholicsolutions will vary as that of the water, when thepressure of the atmosphere is greater or less. Inorder to correct this source of error, a subsidiarybarometrical scale, II, is attached to the thermometer,

F. The method of using this alcoholometer is asfollows:—■

The lamp, A, is lighted; B is filled to about oneinch from the top with the liquid to be examined,to which a paper of common salt is added, and thewhole is then placed on the lamp, A; and lastly, thethermometer, E, is fixed to the scale, with its bulbimmersed in the liquid. Before commencing generaloperations for the day, the boiler, B, is filled withwater, and boiled; if the column of mercury remainsat 29-5, which is placed opposite to 100 on the scaleat the left hand-—the mean boding point of water—no correction is required to be made ; but if it standshigher or lower than this figure, the various boilingpoints of the samples bear reference to this. Intesting the solutions, when the mercury begins torise out of the bulb of the thermometer, the damperis to be pushed in midway into the groove to lowerthe heat. As the liquid bods freely, the mercury inthe tube will become stationary, and the figure on theleft will indicate the percentage under proof, whilethat o.n the right will show the percentage overproof. Field’s alcoholometer only tells the quantityof alcohol, but an auxiliary experiment with thehydrometer will readily give the specific gravity, andupon reference to Table I., the amount of saccharine

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