94 On the Chemical Consiitutmi of 



that the composition of the acid is to be determined, abstracted 

 from this water, and as it exists in combinations in which it is 

 supposed to be in what is called its real state. The principle 

 which I have applied to their constitution leads to very different 

 results. 



In conformity to the law, which it has been shown exists with 

 regard to sulphur, it is probable the oxygen and hydrogen will be 

 in the definite proportions which they separately observe to car- 

 bon. And from the different proportions in which they combine 

 with this element, a number of compounds may be thus formed. 



Carbon, with the first proportion of oxygen, forms an oxide. 

 Hydrogen is an acidifying power. Its addition, therefore, it is 

 not improbable, may give rise to acidity, and its proportion will 

 be determined either by its first or second proportion to carbon, 

 or bv both. Carbon, with its second pro])ortion of oxygen, forms 

 a weak acid. The addition of hydrogen to this will no doubt 

 augment acidity, and its ))roportion will also be determined by its 

 first or second proportion to carbon, or both. Four specific com- 

 pounds will thus be established, which will be represented by car- 

 bonicoxide with a certain proportion of hydrogen ; one, that which 

 exists in carburetted hydrogen; the other, that in supercarburetted 

 hydrogen ; and by carbonic acid with similar proportions of hy- 

 drogen. Further, there has appeared reason to inffr the existence 

 of a relation in proportion of sulphur to oxygen intermediate be- 

 tween that of sulphurous and sulphuric acid; a similar relation 

 may exist in the case of carbon, intermediate between carbonic 

 oxide and carbonic acid ; and with the addition of hydrogen, may 

 give rise to acidity. Lastly, there is some reason also to sup- 

 pose the existence of a combination of sulphur with oxygen in a 

 lower proportion than that in sulphurous acid. There n)av be a 

 similar comliination with carbon, which mav also, with an addi- 

 tional proportion of hydrogen, produce acidity. It remains to 

 inquire how far the composition of any of the vegetable acids can 

 be brought under these laws. 



Carbonic acid is the binary compound of carbon and oxygen. 

 With the addition of hydrogen there is every reason to infer, that, 

 as in the case of all the other binary acids containing oxygen, 

 an acid will be formed of increased power. Oxalic acid is the 

 strongest of the vegetable acids; and the results of its analysis 

 will be found to lead to the conclusion that it is this ternary com- 

 pound. 



Berzelius submitted oxalic acid to experiment by combining it 

 with oxide of lead, drying the oxalate and decomposing it by 

 heat. His object in following this method was to abstract the 

 combined water of the acid, and to operate upon it in what is 

 considered as its real state. He accordingly found, that the acid 



loses 



