m •RELATI ON TO CHEMICAL COMPOSITION. 
377 
Acetic Acid. 
Table III. — Transpiration of Acetic Acid, at 20°, by Capillary C. 
(Transpiration-time of water, 348 seconds.) 
Water added to 100 acid 
(C4H,0,). 
Water, per cent. 
Transpiration-tune. 
Specific gravity, 
at 15°. 
In seconds. 
Water =1. 
0-8 
0-8 
445-5 
1-2801 
15 ... 1 eq. HO 
13-04 
890 
2-5574 
1-0735 
20 
16-66 
921-5 
2-6480 
1-0742 
25 
20-00 
931 
2-6753 
27-5 
21-56 
933 
2-6810 
30 ... 2 eqs. HO 
23-07 
941 
2-7040 
1-0752 
32-5 
24-52 
934 
2-6839 
1-0746 
35 
25-92 
928 
2-6666 
40 
28-50 
912 
2-6207 
45 
31-04 
895 
2 - 571 8 
50 
33-33 
882 
2-5344 
1-0720 
60 ... 4 eqs. HO 
37-50 
852 
2-4482 
1-0700 
90 ... 6 eqs. HO 
47-36 
769 
2-2098 
The glacial acetic acid made use of in these experiments still retained 0'8 per cent, 
of water. Its transpiration-time was 445 ‘5 seconds. With the addition of 1 equiv. 
of water the time rose to 890 seconds ; and ■with 2 equivs. of water to 941 seconds, 
when it attained its maximum. This last is the characteristic hydrate of acetic acid, 
C4H4O4-I-2HO. It is marked out with great precision in these transpiration experi- 
ments. The times rise very gradually on either side, and appear to culminate exactly 
at that point. It is also the compound of -water and acetic acid of maximum density, 
as is weU known. The transpiration-time of the hydrate referred to is so much as 2-7 
times longer than that of pure water. With C equivalents of water acetic acid is still 
transpired 2 ’2 times more slo-wdy than water. 
Butyric Acid. 
Table IY. — Transpiration of Butyric Acid, CgIIg04, at 20°, by Capillary C shortened. 
(Transpiration-time of -wmter, 290 seconds.) 
Water added to 100 acid 
(C'a Hg O 4 ). 
Water, per cent. 
Transpiration-time. 
Specific gravity, 
at 15°. 
In seconds. 
Water =1. 
0 
0 
454 
1-565 
-9740 
10-22 ... 1 eq. HO 
9-27 
828 
2-855 
-9901 
20-45 ... 2 eqs. HO 
16-98 
951 
3-279 
-9975 
30-67 ... 3 eqs. HO 
2.3-47 
969 
3-341 
38-69 ... 4-8 eqs. HO 
27-85 
863 
2-975 
In the transpirability of its hydrates butyric acid presents a considerable analogy to 
acetic acid, as might be expected from the relation of these acids in composition. The 
time of the acid (C8H8O4) is 1-565, referred to that of water as 1, and it rises to 2-855 
by the addition of 1 equivalent of water. By a second equivalent of water the time is 
increased to 3-279. Here, however, the progression does not immediately turn, as with 
