344 Prof. Graham on the Diffusion of Liquids. 



results in the table below represents the diffusion of two cells. 

 These experiments also afford another opportunity of testing 

 the assumed relation between the nitrates and sulphates of the 

 same base. 



Table XIV.— Solution : 1 Salt to 100 Water, at 55°'4— 56°-l. 





Tempe- 

 rature. 



Time in 

 days. 



Square 

 of times. 

 Sol. den- 



Diffusion product of two cells in grs. 



















sity. 



Exp. I. 



Exp. II. 



Exp.III. 



Exp. IV. 



Mean. 



Nitrate of potash 



o 



561 



7 



2 



667 



6-87 



690 



6-57 



675 



Nitrate of soda ... 



557 



8-57 



3 



659 



6-80 



6-94 



657 



678 



Sulphate of potash 



55-4 



9-90 



4 



673 



677 



6-96 



6-68 



678 



Sulphate of soda... 



55-4 



12125 



6 



6-43 



6 94 



6-80 



6-68 



672 



Carbonate of potash 



55-4 



9-90 



4 



6-54 



6-64 



6-40 



667 



6-56 



Carbonate of soda 



55-4 



12125 



6 



6-40 



6-63 



6-60 



667 



654 



The range of temperature during the period of these expe- 

 riments rather exceeded 3 degrees, so that they cannot be 

 considered as fortunate in that respect; but still the similarity 

 between the different sets of experiments, and the near equa- 

 lity of their means, is very remarkable. The two nitrates and 

 the two sulphates may be said to coincide, the extreme differ- 

 ence of the means of the four salts not being quite so much as 

 1 per cent. The two carbonates fall about 3*4 per cent, 

 below the sulphates and nitrates, but agree perfectly with each 

 other, showing a uniformity in their irregularity. This de- 

 viation of the carbonates would appear essential, as it has been 

 observed every time they have been compared with the sul- 

 phates. 



The double relation between salts of potash and salts of 

 soda, and between the nitrate and sulphate class of each of 

 these bases, will, I believe, be allowed to acquire considerable 

 additional support from this new series of observations. 



IV. Diffusion of Sulphate of Magnesia. 



In a set of preliminary experiments upon sulphate of mag- 

 nesia in comparison with sulphate of potash, the 4 per cent, 

 solutions of both salts were diffused for seven days at a mean 

 temperature of 5T 0, 9, with very little fluctuation, the extreme 

 range being from 58°'5 to 57°*75. The sulphate of magnesia 

 is taken anhydrous in all the following experiments. The 

 diffusion of sulphate of potash in three cells was 9" 16, 9*22 

 and 9*57 grs. ; mean 9*32 grs. 



The diffusion of sulphate of magnesia in three cells was 

 5"21, 498 and 5*34 grs.; mean 5*18 grs. The diffusion, in 



