1;30 Remarks on the Preparation of Carhonic Oxide. 



duced to make a complete analysis of the gas obtained after Dr. 

 Mitchell's plan. Taking a given weight of the oxalate of ammonia, 

 and the proportion directed of sulphuric acid, I collected the whole 

 gas evolved from the materials over mercury, that none should be 

 absorbed during the operation. One hundred equal parts having 

 been set aside for examination, pure liquid potassa was thrown up 

 by means of a syringe, and the vessel agitated until no more absorp- 

 tion took place, when fifty parts of the gas had disappeared. The 

 residual gas, on being detonated with oxygen, was found to be nearly 

 pure carbonic oxide. In order to ascertain whether the gas differed 

 in its qualities, at different stages of the process, I collected portions 

 of it at regular intervals, throughout the operation, and subjected them 

 to careful examination. The result of these experiments was pretty 

 uniform, not varying in any case two per cent, from fifty measures of 

 each gas ; and hence I infer, that the oxalate of ammonia, treated as 

 above, for obtaining carbonic oxide, yields the same products as the 

 binoxalate of potassa or oxalic acid, treated according to the methods 

 described in the books. 



Professor Mitchell states, that " on examining the residuary matter 

 left in the retort, it is found to be strong sulphuric acid." I must 

 confess, I am at a loss to know in what way he made an examination, 

 to arrive at such a conclusion, unless it be that he used more than 

 " one or tV(?o drachms of sulphuric acid," for in each case in which I 

 examined the residue, where an ounce of the oxalate and two drachms 

 of acid were used, I found crystals in the retort, after the materials 

 had cooled, answering in every respect to the acid sulphate of ammo- 

 nia. If the quantity of sulphuric acid be increased to four or five 

 drachms, and the heat be stopped a little before the gas ceases to 

 come over, the acid will then hold the sulphate in solution and ex- 

 hibit to the eye an appearance of sulphuric acid ; but a single and 

 very simple experiment — namely, the evaporation of a few drops of 

 the liquid on a platinum or glass capsule, until a part of the acid is 

 expelled, will indicate the presence of some salt, and that, on exami- 

 nation, will be found as above mentioned. That ammonia should 

 escape from the retort, in a free state, while it is in contact with a 

 large excess of free sulphuric acid, and then combine with the car- 

 bonic acid resulting from the decomposition of the oxalic acid, ap- 

 pears to me unphilosophical, and is disproved by experiment, for we 

 recover the whole, or very nearly all the ammonia in combination 

 with sulphuric acid. 



