jtcidSf Alkalis, and their Compounds. 99 



them insulated, and partly from the sources of error which attend 

 the experiment, and which have not been checked or detected 

 by the application of a just principle. It is therefore only from 

 repeated experimental investigation, aided by such an apphcation, 

 that precision can be expected to be obtained. Still some of these 

 results afford very nigh approximations to the views I have il- 

 lustrated. 



The proportions I assign are those founded on the analyses by 

 Berzelius, corrected by the theory I have stated. He combined 

 the acid with oxide of lead, and submitted it to decomposition in 

 this state ; the water of composition he supposed to be thus abs- 

 tracted, and the real acid obtained. But the composition of the 

 acid is in fact subverted, and the water is formed from the com- 

 bination of its hydrogen with a portion of its oxygen. The quan- 

 tity of oxygen thus lost is discovered by the quantity of oxide 

 which the acid saturates, being equal, according to the principle 

 already explained, to the quantity of oxygen in the oxide. The 

 hydrogen lost is the quantity equivalent to this. And these quan- 

 tities of oxvgen and hydrogen being added to the |)roportions as- 

 signed by Berzelius, give the real composition. It is further ne- 

 cessary to remark, that as there has appeared reason to infer the 

 existence of 4 definite proportions of oxygen with sulphur, ob- 

 serving the ratio of 1, 2, 3, -4, and 4 proportions of hydrogen with 

 carbon in the same ratio, so there will be found equal reason to 

 infer the existence of 4 similar proportions of oxygen with car- 

 bon, 100 of carbon being combined in the first with 62"5 of oxy- 

 gen, in the second with 125 constituting carbonic oxide, in the 

 third with 187 "5, and in the fourth with 250 constituting car- 

 bonic acid. With these preliminary observations it is sufficient to 

 give the general results*. 



Citric acid appears to be carbon with oxvgen in the third de- 

 finite proportion, that between carbonic oxide and carbonic acid; 

 and its hydrogen is nearly in the first proportion of that element 

 to carbon. 



Acetic acid is carbon with oxygen in the second proportion 

 nearly, and with hydrogen in exactly the second proportion, that 

 of 100 to IS. It is represented therefore by carbonic oxide, with 

 hydrogen in the proportion which constitutes supercarburetted 

 hydrogen. 



Gallic acid is carbon with oxygen in none of the four definite 

 proportions, but almost exactly in the mean proportion between 

 the first and second. Its hydrogen is nearly in the first propor- 

 tion of that element to carbon. 



Succinic acid is carbon with oxygen in the second proportion, 



• Under the history of the vegetable acids in the 4th volume of System 

 of Chvmixtrij, the precise proportions will be found. 



G 2 that 



