1S15.] Elements of Organic Nature are comhincd. 265 



O'UG'Jo of subsaccharate of lead, equivalent to 0*4 of sugar, 

 produced by combustion from 0*230 to 0-231 of water; and from 

 0-650 to 0-652 of carbonic acid gas. This gives from 6*756 to 

 6*785 per cent, of hydrogen, and from 44-2 to 44*336 of carbon. 

 According to this analysis sugar is composed of 



Hydrogen 6*785 



Carbon 44*200 



Oxygen 49*015 



100*000 



The difference between these two analyses is to be ascribed to 

 the presence of water in the first analysis. It cannot be ascribed to 

 the presence of carbonic acid in the subsaccharate employed ; for 

 this would occasion a diminution in the weight of the carbon found, 

 as well as an augmentation of that of the oxygen, since sugar con- 

 tains much more carbon and much less oxygen than carbonic acid- 



But we have seen that sugar contains five times as much oxygen 

 as the oxide of lead with which it is combined, and ten times as 

 much as the water. Hence it ought to contain, either five or ten 

 volumes of oxygen. When we compare the weights of its elements 

 with one another, we find that it is composed of 100 + 12 C + 

 21 H. This gives per cent. 



Hydrogen 6-802 



Carbon 44*115 



Oxygen 49*083 



100*000 



A result which comes very near the actual analysis. Some readers 

 will probably think it likely that the 21 H ought to be either 20 

 or 24, in order to be double the number of atoms either of oxygen 

 or carbon ; but it is evident, that the difference in the quantities of 

 water which ought to be produced by the combustion of sugar, 

 according to eitlier the one or the other of these suppositions, is so 

 considerable, that it would make a very sensible difference in the 

 result of the analysis. And we shall see afterwards, that such a 

 proportion between the oxygen and hydrogen characterizes the 

 substances which do not yield mucous acid when acted upon by 

 nitric acid. 



To obviate tlie objection that the saccharate analyzed might con- 

 tain some other body besides sugar, I decomposed a certain quan- 

 tity of it by mixing it with water, through which 1 passed a cuiTent 

 of carbonic acid gas. 1 filtered the liquid, and concentrated it. 

 It yielded pure white crystals, which possessed all the properties of 

 common sugar. 



1 likewise burnt a part of it, and obtained from 0*4 of sugar, 

 dried in a vacuum in a hot sand l)ath ; 0*2346 of water, and 0*628 

 oi carbonic acid, which makes in 100 parts 



