36 
PROFESSOR GRAHAM ON THE DIFFUSION OF LIQUIDS. 
be diffused was previously mixed with 100 volumes of air (or any other diluting gas), 
while the 2 volumes of protocarburetted hydrogen were also diluted with 100 volumes 
of air ; the diluting air here representing the water in which the salts to be diffused 
are dissolved in the solution cell. The time in which a certain quantity of protocar- 
buretted hydrogen would come out from a vessel containing 1 per cent, of that gas 
being 1 (the square root of density 1), the time in which an equal quantity of oxygen 
would diffuse out from a similar vessel containing 1 per cent, also would be r4142 
(the square root of density 2). 
(2.) A solution of 4 parts of sulphate of potash in 100 water was diffused simul- 
taneously with the last solution of carbonate of potash, and therefore in similar 
circumstances. The diffusion products of three experiments were 14‘46, 14*21 and 
14*53 grs. ; mean 14*40 grs. This is in the proportion of 104*27 sulphate of potash 
to 100 nitrate of potash ; so that the approximation to equality of diffusion with 
nitrate of potash, in the selected times, is not so close for the sulphate as for the car- 
bonate of potash. 
(3.) The diffusion was repeated of 2 per cent, solutions of the nitrate and carbonate 
of potash at a lower temperature by about 10°. The temperature of the solutions 
was rather unsteady; ranging from 56° to 52°*25 for the first period of seven days, 
from 56° to 50°*5 for the period of 9‘90 days, and from 55° to 50°*5 for a second 
period of seven days; the external atmospheric temperature having fallen during the 
same period more than 20 degrees. Six phials of each solution were diffused and 
evaporated two together ; so that the results are all double quantities. 
At a mean temperature of 54°*3, the nitrate of potash gave in seven days 12*60 
and 12*13 grs.; mean 12*36 grs. 
Again, at a mean temperature of 52°*4, the nitrate of potash gave in seven days 
11*85, 12*40 and 11*95 grs.; mean 12*06 grs. 
The carbonate of potash gave in 9*90 days, with a mean temperature of 53°*4, 12*69, 
12*40 and 12*12 grs.; mean 12*40 grs. 
The general results are — 
Nitrate of potash, in seven days, at 54°*3 . 12*36 grs. 
Carbonate of potash, in 9*9 days, at 53°*4 . 12*40 grs. 
Nitrate of potash, in seven days, at 52°*4 . 12*06 grs. 
As the first nitrate is 0°*9 above the carbonate and the second nitrate 1° below it, we 
may take the mean of the two nitrates as corresponding to the temperature of the 
carbonate. We thus finally obtain, diffused at 53°*4, of — 
Nitrate of potash in seven days, 12*22 grs. . . 100 
Carbonate of potash in 9*9 days, 12*40 grs. . . 101*47 
The difference in the amount of the diffusion of the two salts in these times is only 
0*18 gr., or 1^ per cent. 
These last experiments may be held therefore as tending to the same conclusion as 
