Prof. Graham on the Diffusion of Liquids. 347 



soluble. This is a diffusion of 8'69 grs. for one cell, while the 

 sulphate of magnesia gave 9'05 grs.; or of 100 sulphate of 

 zinc to 104*14 sulphate of magnesia. This result is interesting, 

 as we here find two salts which are isomorphous. and of which 

 the equi-diffusion is on that account in a high degree probable, 

 differing between themselves so much as 4 per cent. 



Another numerous series of experiments was made at a 

 considerably lower temperature, with the view of testing several 

 of the same relations. The temperature in commencing the dif- 

 fusion was 41°, but fell in the course of three days to 38°*8, and 

 afterwards rose to 39°, from which it never varied afterwards 

 more than a degree during the diffusion of the salts of potash 

 and soda. The mean temperature for their periods did not 

 vary above o, l or o, 2 from 39°* 7, so that it may be supposed 

 the same for all these salts. For the sulphates of magnesia, 

 the mean temperature was 38°' 9, or o, 8 lower. The times 

 chosen are as the square-roots of 2, 3, 6 and 16. 



Table XV.— Solutions of 1 and 2 Salt to 100 Water, at 39°*7. 





CO 



.S 



1 



If 



CO 



Diffusion product of two cells 

 in 1 per cent, solutions, and 

 one cell in 2 per cent, solutions. 









> 





Chloride of potassium, 2 percent.... 



9 



11022 

 11022 

 11-022 

 15-589 

 15589 

 25-456 

 25-456 



2 



3 

 3 

 3 

 6 

 6 



16 

 16 



6-58 

 6-66 

 6 33 

 6-50 

 6-60 

 650 

 6-36 

 6-42 



6-79 

 6-98 

 6-63 

 6-60 

 6-56 

 5-43 

 6-20 

 6-78 



6-82 

 679 

 6-73 

 6-64 

 656 

 6-33 

 6-86 

 6-50 



7-06 

 6-74 

 650 



*6 : 59 

 6-84 



6-73 

 6-81 

 6-69 

 6 62 

 655 

 6-42 

 6-50 

 6-63 



Chloride of sodium, 1 per cent 



Chloride of sodium, 2 per cent 





Sulphate of magnesia, 1 per cent.... 

 Sulphate of magnesia, 2 per cent.... 



Several other salts were diffused in the same circumstances 

 as the preceding, of which the diffusion products have been 

 previously given. Of these salts, both the 1 and 2 per cent, 

 solutions of nitrate of potash gave 6'SS in nine days, or in the 

 same time as chloride of potassium in the table. The latter 

 salt maintains a sensible equality of diffusion with the present 

 series at the low, as well as it was found to do at the former 

 high temperature. Chloride of sodium is here introduced for 

 the first time: it appears to be equi-diffusive with nitrate of 

 soda. If the sulphate of magnesia diffused be increased by 

 07, for its lower temperature, this salt will be in close ac- 

 cordance with the salts of potash and soda. 



Taking nitrate of potash 6*83, as 100, for a standard, the 



