C 391 ] 



LVI. Intelligence and Miscellaneous Articles. 



OXIDE OF CARIJON FREE FROM CARBONIC ACID. 



DR. MITCHELL states that he has obtained oxide of carbon of ex- 

 cellent quality, independently of the use of lime water or any 

 other agent for the purpose of detaching carbonic acid, by the action of 

 sulphuric acid on the oxalate of ammonia. The process is as follows: 

 Take an ounce of the oxalate, reduced to powder, and a drachm or 

 two of sulphuric acid, and put them into a six-ounce tubulated retort, 

 and apply a very gentle heat. In a few minutes large quantities of 

 gas are evolved, and may be collected in the usual manner over water. 

 If the heat be duly moderated, the first and last products, as obtained 

 in the receivers, will be pure carbonic oxide gas. The sulphuric acid 

 seems to act by resolving the oxalate into oxalic acid and ammonia j 

 then to decompose the oxalic acid into its elements, and to put the 

 whole into such a state as to enable the constituents to recombine so 

 as to form the pure gas. That carbonic acid is actually evolved, can- 

 not be doubted, but it seems to join the ammonia instantly, forming 

 carbonate of ammonia, which is absorbed by the water as fast as it is 

 produced. If it is inquired how it happens that the sulphuric acid 

 does not instantly seize the ammonia and form a sulphate, Dr. M. ob- 

 serves, that although the moderate heat employed is amply sufficient 

 to drive over the gaseous elements of the oxalate, it is inadequate to 

 cause the sulphuric acid to do so. 



The above statement will be better understood by the use of a dia- 

 gram j premising, that the equivalents or combining numbers of the 

 several articles are as follow: oxalic acid 36, made up of 24, or 3 

 equivalents of oxygen, and 12, or 2 equivalents of carbon; ammo- 

 nia \7, making the salt 53 ; carbonic acid 22, made up of 16, or 2 

 equivalents of oxygen, and 6, or 1 equivalent of carbon ; carbonic 

 oxide 14, composed of 8, or 1 equivalent of oxygen, and 6, or 1 

 equivalent of carbon. 



' oxygen 8 14 carbonic oxide. 



oxygen 8> 

 oxygen 8 , 

 carbon 6-^ 



36 oxalic acid, 



carbon 6^ > \X 



\ 39 carb. 



carbon 6 -22 c. acid v 



ammonia. 



17 ammonia 17 am'nia 



53 53 



■ 



3 

 3 

 c 



1-j 



If a very gentle heat be continued for some time, the same pro- 

 ducts will be had, independently of the use of sulphuric acid ; but 

 the latter seems to accelerate the process. 



When we employ oxalic acid to make the carbonic oxide gas, a 

 portion of carbonic acid is unavoidably formed, and must be removed 

 by means of lime water. In like manner, this acid gas is generated 

 or evolved when the oxalate of ammonia is used ; but as it combines 

 instantly with the ammonia, it does not contaminate the desired pro- 



