180 
PROFESSOR GRAHAM ON OSMOTIC FORCE. 
Millimeters. 
Sulphate of potash, saturated solution, at 58° 16-3 
Sulphate of soda, 1 per cent., at 55° 1 7*75 
Sulphate of soda, 10 per cent., at 58° 16-95 
Hydrochloric acid, 1 per cent., at 63° 17*5 
Sulphuric acid, 0*1 per cent., at 63° 17'4 
Sulphuric acid, 1 per cent., at 63° 16-35 
Sulphuric acid, 5 per cent., at 63° 16-65 
Sulphuric acid, 10 per cent., at 63° 16'25 
Sulphuric acid, undiluted (HO S0 3 ), at 63° 8‘1 
Oxalic acid, 1 per cent., at 66° 17‘35 
Oxalic acid, 4 per cent., at 62° 17’2 
Ammonia, 0’1 per cent., at 66° 16"65 
Ammonia, 1 per cent., at 66° 16T5 
Ammonia, 12 per cent. (0’943 sp. gr.), at 66° 15-05 
Sugar, 10 per cent., at 65° -. 163 
Alcohol, 0‘8 per cent. (0‘9985 sp. gr.), at 60° 15*5 
Alcohol, 4’5 per cent. (0-992 sp. gr.), at 63° 13‘2 
Alcohol, 7*8 per cent. (0‘987 sp. gr.), at 60° 11-05 
Alcohol, 71 per cent. (0’869 sp. gr.), at 63° 6’ 
Alcohol falls in the greatest degree below water in capillarity, yet the former sub- 
stance is one of the least remarkable for the power to occasion osmose. 
The newer facts to be related also increase the difficulties Fig. l. 
of the capillary theory of osmose. 
My own experiments on osmose were made with both mine- 
ral and organic septa. 
I. A convenient earthenware or baked clay osmometer is 
easily formed by fitting a glass tube and cover to the mouth 
of the porous cylinder, often used as a cell in Grove’s battery, 
as in fig. 1 ; the cylinder was generally 5 inches in depth by 
1*7 inch in width, inside measure, and was capable of bolding 
about six ounces of water. Gutta percha is much preferable 
to brass as the material for the cap or cover. The glass tube 
above was also comparatively wide, being 0*6 inch or 15 mil- 
limeters in diameter, and was divided into millimeters. It 
was not more than 6 inches in length. Each of the divisions 
or degrees amounted approximatively to y^th part of the 
capacity of the clay cylinder. 
In conducting an experiment, the cylinder/always pre- 
viously moistened with pure water, was filled with any saline 
solution to the base of the glass tube, and immediately placed in a jar of distilled 
water, of which the level was kept adjusted to the height of the liquid in the tube of 
