of Potash on Organic Matter. 369 



give hydrogen, which must come from the substance itself or 

 from water, and at last they yield carbonic acid. Animal 

 matters, besides these products, give ammonia and cyanogen. 

 Water may also be formed with animal, as well as with vege- 

 table substances. These various products, or merely some of 

 them, are sufficient to explain in general the formation of ox- 

 alic acid ; nevertheless in some particular cases, it would ap- 

 pear that other products must be obtained : thus tartaric acid 

 yielding no sensible quantity of hydrogen, we cannot, consi- 

 dering its composition as 



2^ proportions of hydrogen, 



4. of carbon, 



5 of oxygen, 



explain its conversion into oxalic acid, except by the formation 

 of the probable compound already mentioned. 



In fact, during the operation the mass remains white, and 

 does not carbonize. If all the carbon entered into the com- 

 position of the oxalic acid, it would require six proportions 

 of carbon ; and consequently the water must be decomposed 

 to supply one proportion. If only such a quantity of oxalic 

 was formed, as is proportional to the oxygen contained in the 

 tartaric acid, there would remain two-thirds of a proportion 

 of carbon which might form a peculiar compound with the 

 hydrogen, and for one proportion of tartaric acid. If propor- 

 tion of oxalic acid would be procured. I did in fact obtain, 

 at least 1^; but I have not yet discovered any other hydro- 

 genated product. Lasdy, it is possible that with carbon, hy- 

 drogen and oxygen, a peculiar acid might be formed. This 

 subject, it will be admitted, requires additional examination. 

 I conclude by mentioning a very elegant process for convert- 

 ing tartar into oxalate of potash. — It consists in dissolving 

 crude tartar in water, with a proper quantity of potash or 

 soda, and passing the solution continually through a thick 

 iron tube by means of a pump, at a temperature of 200° to 225° 

 Centig. The pressure will not exceed twenty-five atmospheres, 

 because no gas will be evolved. A valve placed at the end 

 opposite to that at which the solution enters, is to be loaded 

 with .'f weight sufficient to produce this pressure, and it will 

 open only by the contrary pressure of the injecting pump. 

 I have not yet tried this process, which may also be applied 

 to other substances ; but 1 see nothing which opposes its suc- 

 cess. According to some experiments which I have made, it 

 requires less than one proportion of potash for one proportion 

 of neutral tartrate. 



A^..S'. Vol. G. No. 35. Nov. 1829. 3 B LIX. lihto- 



