ALCOHOL.— Alcoiiolometry. Tralles’ Tables.
127
Tralles’ Table II.—Concluded.
Per cent.,bwolume,n? absolutealcohol.
Spec. grav.of the liquidat 60°.
Decrease of spec. grav. at the indicated temperatureabove t>0°.
«5®
70°
75®
80®
85°
90®
95°
100°
0
0-9991
1
n
17
24
32
40
50
60
5
9919
1
11
18
25
33
42
51
62
10
9857
6
13
20
29
37
47
57
68
15
9802
7
15
25
34
44
55
67
79
20
9751
9
19
30
41
53
66
79
93
25
9700
11
24
36
50
63
78
93
109
30
9646
14
28
43
59
75
91
108
125
35
9583
17
33
50
68
86
104
122
141
40
9510
18
37
56
75
94
114
136
154
45
9427
20
40
60
80
101
122
143
154
50
9335
21
42
63
84
106
128
150
173
55
9234
22
43
65
87
109
132
155
178
60
9126
22
44
67
90
113
136
150
183
65
9013
22
45
68
92
115
138
162
187
70
8892
23
46
69
93
117
141
165
190
75
8765
23
46
70
94
119
143
167
192
80
8631
23
47
71
96
120
144
169
194
85
8488
24
48
72
96
121
145
170
195
90
8332
24
48
72
97
121
146
171
.196
A further objection to these tables is, that thespecific gravity of the mixtures of alcohol and waterat elevated or reduced temperatures is not the realbut the apparent density. The cause of this dis-crepancy is, that the glass or copper vessel in whichthe liquids are weighed are liable to expand orcontract with change of temperature,
Tralles constructed a third table, in order that thepercentage by volume in an alcoholic liquid mightbe ascertained from the more uniform arrangementof the numbers denoting the specific gravities.
In Table III. the densities are given of the severalmixtures from 30° to 85°, as ascertained by a glassinstrument; but these numbers, by the aid of theallowance, as seen in Table IV., can be made tocorrespond with the indications of a brass alcoholo-meter.
The necessity for using Table IV. arises fromthe discrepancy in the contraction or expansionof glass or brass at different temperatures, occasioning
Tralles’ Table III.
Per cent.
Specific gravity of the liquid, ascertained by glass instruments, at the indicated temperatures.
by volume.
30®
z:°
40°
45°
50*
00*
65°
70°
76”
81 P°
85®
0
•9994
•9997
■9997
•9998
•9997
•9994
•9991
•9987
•9981
■9976
•9970
■9962
5
9924
9926
9926
9925
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
9723
9713
9701
25
9752
9745 •
9737
9729
9720
9709
9700
9690
9678
9666
9653
9640
30
9715
9705
9694
9683
9671
9658
9646
9633
9619
9605
9590
9574
35
9668
9655
9641
9627
9612
9598
9583
9567
9551
9535
9518
9500
40
9609
9594
9577
9560
9544
9527
9510
9493
9474
9456
9438
9419
45
9535
9518
9500
9482
9464
9445
9427
9408
9388
9369
9359
9329
50
9449
9431
9413
9393
9374
9354.
9335
9315
9294
9274
9253
9232
55
9354
9335
9316
9295
9275
9254
9234
9213
9192
S171
9250
9128
60
9249
9230
9210
9189
9168
9147
9126
9105
9083
9061
9039
9016
65
9140
9120
9099
9078
9056
9034
9013
8992
8909
8947
8924
8901
70
9021
9001
8980
8958
8936
8913
8892
8870
8847
8825
8801
8778
75
8896
8875
8854
8832
8810
8787
8765
8743
8720
8697
8673
8649
80
8764
8743
8721
8699
8676
8653
8631
8609
8585
8562
8538
8514
85
8623
8601
8579
8556
8533
8510
8488
8465
8441
8418
8394
8370
90
8469
8446
8423
8401
8379
8355
8332
8309
8285
8262
8238
8214
Tralles’ Table IV.
To be subtracted.
To be added.
30°
35°
40°
45°
50°
55"
60*
05°
70°
75°
80°
85®
•0005
•0004
■0003
•0002
•0002
•0001
-
•0001
•0002
•0002
■0003
•0004
variation in the density; hence these numbersmust be added or subtracted, as directed, accord-ing to the temperature, when a brass instrumentis employed.
It occurs that liquids are tested whose temperatureand specific gravity are intermediate between thoseinstanced in the preceding table, and in this case thecorresponding content of alcohol must be found bycalculation. To give an example:—Let it be supposedthat the specific gravity of an alcoholic solution hasbeen found by experiment to be '9320 at a tempera-ture of 72° Fahr. In the column under 70°, thespecific gravity '9388 is that which is next over theabove number, and in the column under 75° thegravity nearest to it is '9369, both of which exceed'9320—the former by '0068, and the latter by '0049.
The difference between these two numbers is '0019,which is the variation for 5°, or between 70° and
o ‘0019 ,
75 , and by dividing by 5, the quotient is ——, the
difference for each degree. As the temperature ofthe liquid under examination is 72°, or 2° over 70°,it is necessary to reduce the specific gravity to whatit would indicate were the liquid at 70°, by adding a„ '0019 , -0038
multiple of —g— by 2, or . = -0007|- to the
specific gravity obtained.—'9320—which would makeit '9327f, or omitting fractions, -9327. By referringto the table, will be seen in the horizontal columnopposite 45 per cent, of alcohol, and under 70°, thespecific gravity '9388, and in the same column, in a