Prof. Graham on the Diffusion of Liquids. 195 



It is to be observed, that in preparing the ammoniated salts, 

 the solutions of the neutral salts of copper were slightly diluted 

 by the water of the solution of ammonia added to them, so 

 that the proportion of salt of copper which they possessed was 

 sensibly reduced below 4 per cent. On the other hand, the 

 copper salt which diffused out is estimated, not as ammoni- 

 ated, but as neutral salt. It will be observed that the quantity 

 of sulphate of copper diffused out in the experiments falls from 

 6*35 in the neutral salt to 1*44 gr. in the ammoniated salt; 

 of nitrate of copper from 9*77 to 1*56, and of chloride of cop- 

 per from 10'65 to 4*24. These numbers are to be taken only 

 as approximations; they are sufficient however to prove a 

 much reduced diffusibility in the ammoniated salts of copper. 



It will be remarked that the nitrate of ammonia and chlo- 

 ride of ammonium approximate, 1580 and 16*59 grs. ; as do 

 also the nitrate and chloride of copper, 9*77 and 10'65 grs.; 

 the chlorides, which were diffused at the higher temperature 

 by 2 0, 8, exceeding the nitrates in both cases. 



4. Diffusion of Mixed Salts. 



When two salts can be mixed without combining, it is to 

 be expected that they will diffuse separately and independently 

 of each other, each salt following its special rate of diffusion. 



(1.) Anhydrous sulphate of magnesia and sulphate of water 

 (oil of vitriol), one part of each, were dissolved together in 10 

 parts of water, and the solution allowed to diffuse for four 

 days at 6i°*5. 



The water -^jar was found to have acquired — 



Sulphate of magnesia . . . 5*60 grs. 

 Sulphate of water .... 21*92 grs. 



27*52 grs. 



The experiment with the same diffusion cell and liquid 

 being continued for a second period, this time of eight days, 

 there was found to be simultaneously diffused, of — 



Sulphate of magnesia . . . 9*46 grs. 

 Sulphate of water .... 29*32 grs. 



38*78 grs. 



It is obvious that the inequality should be greatest in the 

 first period of diffusion, or with the initial diffusion, as it ac- 

 tually appears above, and become less and less sensible as the 

 proportion of the low diffusive salt comes to be increased in 

 the solution phial. 



In former experiments upon the solution of sulphate of 



02 



