Aqueous Solutions of Acids and Alkalies, 



465 



sugar is 192*32 septems, or equal to that of 12 test atoms of 

 water. Its measure in solution varies from 194*24 septems 

 to 176*02 septems. Hence, in one very dilute solution of 

 sugar, its atomic volume, as stated by Dalton and by Messrs, 

 Playfair and Joule (Phil. Magazine, vol. xxviii. page 470), 

 is equal to that of 1 1 atoms of water, but, in highly concen- 

 trated solutions, its atomic volume, according to the experi- 

 ments both of Dr. Ure and of Messrs. Playfair and Joule, is 

 equal to more than that of 12 atoms of water. Sugar, there- 

 fore, has no fixed atomic volume in solution. It does not 

 uniformly add to the bulk of the water of solution, a volume 

 equivalent to its own oxygen and hydrogen estimated as water. 

 Nor does its carbon cease to occupy space in solution. In 

 short, Dalton's experiments on this subject are incorrect, his 

 hypothesis is untenable, and the application of this method of 

 analysis to organic bodies is impossible. Witness, acetic acid. 



Table XX. — Sulphate of Magnesia. 



MgO, S0 3 = 759*518 grs. Temperature 62° F. 

 MgO, SO 3 + 7 H 2 = 1546*878 grs. 



Observations on the Table of Sulphate of Magnesia. 



Sulphate of magnesia is a substance regarding whose pe- 

 culiar properties Messrs. Playfair and Joule are in strict ac- 

 cordance with Dr. Dalton. They find, with him, that when 

 it dissolves in water it occupies no space in solution (Phil. 

 Magazine, vol. xxviii. p. 470). 



