IX EELATION TO CHEMICAL COMPOSITION. 
383 
Table XII. — Transpiration of Glycerine, at 20°, by Capillary C. 
(Transpii’ation-time of water at the same temperature, 348 seconds.) 
1 "Water added to 100 Glycerine 
TeHsOg). 
Water, 
per cent. 
Transpirs 
In seconds. 
ition-time. 
Water =1. 
Specific gravity, 
at 15°. 
170 
62-96 
1199 
3-445 
1-1010 
1 76-07 ... 18 eqs. 
63-77 
1160 
3-333 
1-0980 
180 
64-28 
1131-5 
3-251 
1-0960 
190 
65-51 
1068-5 
3-070 
1-0934 
192 
65-75 
1054 
3 031 
1-0927 
195 
66-10 
1049 
3-014 
1-0914 
197 
66-32 
1039 
2-977 
1-0912 
200 
66-66 
1026 
2-948 
1-0905 
The transpiration-time of 18-hydrate is 3-333, referred to water as 1. There is no indi- 
cation of a maximum at that point, but the numbers descend according to their place in 
the Table without any interruption. 
The idea having suggested itself that the \iscous property of glycerine solutions might 
overpower or conceal the expected de-viation, the transpiration was repeated at a higher 
temperature, when the solutions possess greater fluidity. 
Table XIII. — Transpuation of Glycerine, at 60°, by Capillary C. 
(Transpiration-time of water at the same temperature, 186 seconds.) 
Water added to 100 Glycerine 
(Ce 11s Oe). 
Water, per cent. 
Tran spir ation -time. 
Specific gravity, 
at 1.5°. 
In seconds. 
Water =1. 
170 
62-96 
435-5 
2-341 
1-1010 
172-5 
63-30 
432 
2-322 
1-0999 
175 
63-63 
428 
2-301 
1-0980 
176-08 ... 18 eqs. 
63-77 
425 
2-284 
1-0976 
177 
63-96 
422-5 
2-271 
1-0970 
180 
64-22 
420 
2-258 
1-0960 
Still no retardation appears at the point of 18 equivalents, but the time continues to 
shorten as the proportion of water is increased, according to a pretty uniform progression. 
The information respecting the constitution of glycerine which transpiration affords is 
therefore of a negative character. 
The existence of a relation between the transpirability of liquids and their chemical 
composition appears to be established. It is a relation analogous in character to that 
subsisting between the boiling-point and composition, so well defined by M. Kopp. Per- 
haps the most interesting part of the present subject to develope would be the transpira- 
tion of homologous series of substances. Judging from the limited observations on the 
alcohols, ethers, and acids, the order of succession of individual substances in any series 
would be indicated by the degree of transpirability of these substances, as clearly as it 
IS by their comparative volatility. In carrying out the inquiry, it would probably be 
