Prof. Graham on the Diffusion of Liquids, 193 



upon equal solubility, for in none of the pairs is there any ap- 

 proach to equality in that respect. 



A comparison was now made of the diffusibility of several 

 acids. They were diffused from the same six-ounce phials, 

 and for eight days. Solutions were prepared in the proportion 

 of 4 parts of the anhydrous acid to 100 parts of water. The 

 quantity of acid which diffused into the water-jar was estimated 

 by the proportion of carbonate of soda which it neutralized. 



Table V. — Diffusion of acid solutions (4 acid to 100 water) 



at 59°*3. 



Name of acid. 



Density of 

 solution at 60°. 



Anhydrous acid diffused. 



In grains. 



Means. 



Nitric acid 



10243 

 10225 

 10317 

 1-0094 

 10235 

 1-0320 

 10194 

 10284 

 1-0285 



29-21 



28-19 



34-22 



33-99 



18-71 



18-26 



1913 



1719 



12-38 



12-38 



1216 



1216 



9-90 



9-69 



9-09 



909 



12-32 



28-7 



341 



18-48 



1816 



12-38 



1216 



9-79 



9-09 

 12-32 



Hydrochloric acid 



Sulphuric acid 



Acetic acid 



Oxalic acid 



Arsenic acid 



Tartaric acid 



Phosphoric acid 







Considerable latitude thus appears to exist in the diffusibi- 

 lity of the different acids. To make the result for nitric acid 

 fairly comparable with that for hydrochloric acid, the former 

 should be increased in the proportion of 54 to 63, that is esti- 

 mated as nitrate of water. This calculation gives 33*5 grs. 

 of nitrate of water diffused, which approaches closely to 34*1 

 grs., the quantity for chloride of hydrogen or hydrochloric 

 acid. The quantity of soda neutralized by the sulphuric and 

 hydrochloric acids diffused was as 14*32 to 28*97, or nearly 

 as 1 to 2. Sulphuric and acetic acids, on the other hand, 

 appear to be equally diffusible. Phosphoric acid is the least 

 diffusible acid in the series, presenting only about half the 

 diffusion product of the two last-mentioned acids. The solu- 

 tion of phosphoric acid had been boiled for half an hour be- 

 fore diffusion, and was therefore in the tribasic state. The 

 same precaution was not thought of for arsenic acid, although 

 it is possibly required by this acid also. These two acids do 

 not exhibit the equality of diffusion anticipated from their 

 recognized isomorphism, but it is to be stated that the acidi- 



Phil Mag. S. 3. Vol. 37. No. 249. Sept. 1850. O 



