216 
PROFESSOR GRAHAM ON OSMOTIC FORCE. 
Hydrate of Lime exhibited similar characters to the last base. Undiluted lime- 
water gave in doable membrane —20 ms. and — 1 m. ; while the same, diluted with 
four volumes of water, gave a positive osmose of 31 and 18 ms. In albumen the 
undiluted lime-water gave —48 and —30 ms.; the same, diluted with four volumes 
of water, gave 0 m. and 1 m. 
Chloride of Strontium , 1 per cent., gave in double membrane 19, 2 7 and 26 ms., 
following chloride of barium in the same membrane, 13 and 21 ms. Nitrate of baryta, 
in the same membrane, gave 12, 24 and 29 ms. ; nitrate of strontia, following the 
latter, 2/ and 31 ms. 
Nitrate of Lime in membrane twice gave 19 ms., following chloride of calcium 
with 12 and 20 ms. ; in albumen nitrate of lime gave 2 and 2 ms. 
The two per cent, solution of the same salt in membrane gave only 6 and 6 ms. in 
two experiments. 
Chloride of Magnesium gave in membrane —2 ms. and in albumen 6 ms., both 
experiments being made with the one per cent, solution, which is always to be un- 
derstood when no particular per-centage is stated. 
Nitrate of Magnesia gave in membrane —24 and — 20 ms. Both of these mag- 
nesian salts were prepared by saturating the acid with excess of magnesia! The 
tendency of monobasic salts of the magnesian class to chemical osmose of a nega- 
tive character appears to be small in the salts of barium and strontium, to rise in 
those of calcium, and to culminate in the salts of magnesium itself. 
Aluminium. — Nothing is more remarkable than the high positive osmose of certain 
salts of alumina. These salts emulate the alkaline carbonates in this respect. The 
property too appears to be characteristic of the sesquioxide type, and distinguishes 
the salts of sesquioxide of iron, sesquioxide of chromium and the higher oxide of 
uranium, as well as alumina. 
Sulphate of Alumina. — The sulphates of this type do not exhibit a high degree of 
osmose, although they are probably more osmotic than the magnesian sulphates as a 
class. Sulphate of alumina, 1 per cent., gave in membrane 57 and 67 ms., and for 
0T per cent. 24 and 31 ms. 
The dilfusate was small, amounting in the second observation of the J per cent, 
solution to 0 033 gramme of tersulphate of alumina, together with an excess of 0‘005 
grm. of sulphuric acid, according to analysis. 
Chloride of Aluminium, prepared by treating hydrochloric acid with an excess of 
hydrated alumina, was found by analysis to approach very nearly to the proportions 
of the definite compound Al 2 Cl 3 . The following results with that salt were suc- 
cessively obtained in an osmometer of single membrane : — 
With 1 per cent., rise of 540 ms. at 50° Fahr. 
With 1 per cent., rise of 570 ms. at 49° 
With 1 per cent., rise of 450 ms. at 47° 
With 1 per cent., rise of 635 ms. at 49° 
33 
