983 



This acid appears to be considerably less diffusive than sulphuric 

 acid. 



Sulphurous Acid, — Diffusion of sulphurous acid in ten days at 



68°-l ; two cells 



Grs. Ratio. 



From 1 per cent, solution 8*09 0*954? 



From 2 per cent, solution 16*96 2 



From 4 per cent, solution 33*00 3*891 



From 8 per cent, solution 66*38 7*827 



This substance appears to be less diffusive than sulphuric acid at 

 the same temperature ; the diffusion of sulphurous acid at 68°*1 con- 

 siderably resembles that of sulphuric acid at 4'9°*7. 



Ammonia. — Diffusion of ammonia in 4*04 days, the time of hy- 

 drate of potash, at 63°*4 ; two cells : — 



Grs. Ratio. 



From 1 per cent, solution 4*93 1*029 



From 2 per cent, solution 9*59 2 



From 4 per cent, solution 19*72 4*117 



From 8 per cent, solution . „ 41*22 8*605 



Ammonia appears to have a diffusibility approaching to that of 

 hydrate of potash. It appears very similar to hydrocyanic acid at 

 the same temperature ; or to possess about three-fourths of the dif- 

 fusibility of hydrochloric acid. 



Alcohol. — Time of diffusion ten days. The quantity of alcohol 

 diffused was determined by careful distillation. The density of the 

 alcohol solutions in the phials was always made to exceed that of 

 the water in the jars, by the addition of chloride of sodium to the 

 former. 



Diffusion of alcohol in ten days at 48°*7 ; two cells : — 



From 2 per cent, solution 8*62 



From 4 per cent, solution 16*12 



From 8 per cent, solution 35*50 



Alcohol does not appear to belong to the same class of diffusive 

 substances as acetic acid, which might be expected from their simi- 

 larity of composition, but possesses a considerably lower diffusibility. 



Diffusion from 2 per cent, solutions in ten days : — 



Acetate of water at 48°*8 11*51 100 



Alcohol at 48°*7 8*62 74*9 



The diffusion of alcohol approaches to one-half of that of sulphate 

 of water at nearly the same temperature. 



Alcohol may be substituted for water to dissolve certain salts, and 

 at the same time be made an atmosphere into which these salts are 

 allowed to diffuse. From experiments which have been commenced 

 on this subject, it appears that the diffusion of hydrate of potash, 

 iodide of potassium, chloride of calcium and others is about four 

 times slower into alcohol of density 0*840 than into water. The salts 

 likewise often exhibit the same relations in their diffusibility in alco- 



