ALCOHOL.— Alcoholojietry. Tralles’ Tables.
128
line with 50 per cent, of spirit, "9294, whose differencefrom the foregoing is -0094; thus the variation ingravity at the same temperature, for 5 per cent, ofalcohol, is "0094. In like manner, the difference of•9388 and '9327, the reduced gravity for the liquidspecified, is ’0061; and since 5 per cent, of spirit hasbeen shown to correspond with '0094, it is found bysimple proportion that -0061 will be equivalent to3'24 per cent., and this, added to 45 per cent., thespirit in the liquid of gravity next preceding thatwhich is supposed to be ascertained, gives 48-24 asthe percentage by volume of alcohol. Numerically—•9388 — -9320 = -0068, and•9369 — -9320 = -0049.
By subtracting the lesser of these from the greater,namely, '0068— "0049 — "0019, the difference for the5° between 70° and 75° Fahr., giving for each degree•0019
—r—; and to reduce the corresponding gravity of the0
liquid at 72° to that of 70°, there must be added to it
■0019
5
X 2 (= 72
70) =
•0038
5
= '0007§-; and thus
one obtains -9320 + •0007-§ = -9327^, or omittingfractions, -9327. Again,
•9388 — -9294 = -0094, and•9388 — -9327 = -0061.
And since the former indicates a difference of 5 percent, in the amount of alcohol, at the same tempera-ture, the equivalent for '0061 under similar circum-stances is obtained by simple proportion :—
As 94 : 5 :: 61 : 3'24, which, when added to 45, gives48 - 24, the content per cent, by volume of alcohol inthe liquid. From all the tables in the foregoing forthe determination of the volume of alcohol in a liquid,at whatever temperature it may stand, it is seen thatreference is always had to the percentage at thenormal temperature of 60° Fahr. Hence, in examin-ing an alcoholic liquid for its true content of purealcohol, the heat must be diminished to 60°, or elsethe temperature noted at the time of experiment,and then by calculation reduced to 60°; or the contentof alcohol at 60° may be found as in Table II., wherethe specific gravity at the different temperatures is ininverse proportion to the volume of alcohol.
To avoid this calculation, Tralles calculatedanother table, which gives the content in volume ofabsolute alcohol in a liquid, reference being had tothe bulk of the liquid at the temperature at which itis measured.
For the prevention of error, it is absolutely necessaryto determine the specific gravity of the liquid at thesame degree at which it stands when measured; aglass instrument should be employed.
Thallf.s’ Table V.
To ascertain at any temperature, from the specific gravity, the quantity of absolute alcohol in a liquid expressed involume centesimally, at the indicated temperature.
Specific gravity of the liquid, ascertained by glass instruments, at the indicated temperatures.
in the liquid nsmeasured.
30°
S5»
40°
45°
co°
55°
G0°
cs®
70®
75®
80®
85®
0
0-9994
•9997
•9997
•9998
•9997
•9994
•9991
•9987
•9981
•9976
•9970
•9962
5
9924
9926
9926
9926
9925
9922
9919
9915
9909
9903
9897
9889
10
9868
9869
9868
9867
9865
9861
9857
9852
9845
9839
9831
9823
15
9823
9822
9820
9817
9813
9807
9802
9796
9788
9779
9771
9761
20
9786
9782
9777
9772
9766
9759
9751
9743
9733
9722
9711
9700
25
9753
9746
9738
9729
9720
9709
9700
9690
9678
9665
9652
9638
30
9717
9707
9695
9684
9672
9659
9646
9632
9618
9603
9588
9572
35
9671
9658
9644
9629
9614
9599
9583
9566
9549
9532
9514
9495
40
9615
9598
9581
9563
9546
9528
9510
9491
9472
9452
9433
9412
45
9544
9525
9506
9486
9467
9447
9427
9406
9385
9364
9342
9320
50
9460
9440
9420
9399
9378
9356
9335
9313
9290
9267
9244
9221
55
9368
9347
9325
9302
9279
9256
9234
9211
9187
9163
9139
9114
60
9267
9245
9222
9198
9174
9150
9126
9102
9076
9051
9026
9000
65
9162
9138
9113
9088
9063
9038
9013
8988
8962
8936
8909
8882
70
9046
9021
8996
8970
8944
8917
8892
8866
8839
8812
8784
8756
75
8925
8890
8873
8817
8820
8792
8765
8738
8710
8681
8652
8622
80
8798
8771
8744
8716
8688
8G59
8631
8602
8573
8544
8514
8483
85
8663
8635
8606
8577
8547
8517
8488
8458
8427
8396
8365
8333
90
8517
8486
8455
8425
8395
8363
8332
8300
8268
8236
8204
8171
Tralles' Table VI.
To be added.
To be subtracted.
so®
35®
40®
45®
50"
55®
60°
65°
7C®
75®
80"
85®
•0005
•0004
•0003
•0002
•0002
•0001
—
•0001
•0002
•0002
•0003
•0004
For the reasons assigned under Tables in. andIV. , the numbers in Table VI. must be added orsubtracted, as may be deemed necessary, to or fromthe specific gravities given in Table Y., according tothe temperature.
From the above tables, the true amount of alcohol
in a liquor, or “its richness,” may be ascertained bythe specific gravity.
It will be as well to consider here the method usedfor ascertaining the specific gravity of the variousliquids. The density is invariably found by one oftwo methods—either by actually weighing- a portion