1892-93.] Prof. Tait on Compressibility of Aqueous Solutions, 143 
Magnesium Sulphate — 
13-836 16-058 
6°-8 1-1489 
ir -2 
1-1479 
9-508 10-507 
5°-8 1-1005 
13°-1 
1-0990 
5-869 6-235 
5°-7 1-0614 
12°-1 
1-0602 
Barium Chloride — 
13-798 16-006 
5°-8 1-1366 
ll°-2 
1-1354 
9-096 10-006 
5°-8 1-0869 
13°-1 
1-0855 
4-585 4-805 
5°-6 1-0423 
12°-2 
1-0416 
To these may be added 
[ the following. 
due to Dr 
Gibson, from 
my Challenger Keport referred to. 
0° C. 
6° C. 
12° C. 
Sodium Chloride — 
17-6358 
1-138467 
1-136040 
1-133565 
13-3610 
1-101300 
1-099341 
1-097244 
8-8078 
1-067589 
1-066144 
1-064485 
3-8845 
1-029664 
1-028979 
1-027935 
Although I made at least two observations at each of the pres- 
sures 1, 2, and 3 tons, on each solution, in each of two piezometers, 
1 publish in this Abstract nothing beyond some mean results at one 
temperature and for one pressure: — viz. 12° C. and 2 tons. These 
are fairly representative of the whole work. The columns of 
mercury used in calibration corresponded nearly with the parts of 
the tubes concerned in the measured compression at that pressure ; 
and, on such lengths of tube, errors of measurement due to slight 
changes of temperature of the solution, &c., are comparatively 
insignificant. 
The change of (unit) volume of water per ton at 12° C. and 
2 tons is (by my former work) 
0-2474 
36 -h 2 
0-00651 . 
If to the 36 in this expression be added the product of the quantity 
s below given for any one salt, multiplied by the per-centage of the 
salt, we have the numbers in the column headed Calc. Those 
headed Ohs. were obtained as stated above ; and the agreement is 
on the whole satisfactory. The old determinations for common 
salt are included in the table, though they show rather less con- 
cordance than the others. 
