144 COMBUSTIBLE ACIDS. 



tions of the constituents, answering to the ato- 

 mic weight 15 of the acid approaches so very 

 nearly to 



6 atoms hydrogen O75 



15 atoms carbon 11-25 



3 atoms oxygen 3 



15 



that we can have no hesitation in admitting that 

 these represent the true atomic constituents of 

 the acid. It is therefore a very complicated 

 body, as it contains no fewer than 24 atoms. 

 Like all other very complex bodies its affinities 

 are very weak. 



SECT. VII. 



OF THE ATOMIC WEIGHT OF SACLACTIC ACID. 



I HAVE prepared this acid both from sugar of 

 milk and from gum. The acid obtained from 

 gum is always contaminated with saccolate of 

 lime ; the best way of freeing it from which is 

 to dissolve it in water. The saccolate of lime 



tion of sac- 

 lactic acid, remains behind, and may be separated by the 



filter. Then by evaporating the aqueous solu- 

 tion to dryness by a gentle heat, we recover the 

 saclactic acid in a state of purity. But great 

 care must be taken not to expose the evaporat- 



