Intelligence and Miscellaneous Articles. 153 



of a silvery whiteness, perfectly ductile and malleable, fusible at a 

 comparatively low temperature, and, like zinc, capable of sublima- 

 tion at a temperature very little higher than that of its fusibility, 

 and condensing under the form of small globules. It does not de- 

 compose water at the ordinary temperature; it oxidizes at a high 

 temperature and is converted into magnesia, slowlj' when it is in 

 rather large pieces, but when it is in fine dust it burns with great 

 splendour, throwing out sparks like iron in oxygen gas. — Royal 

 List. Journal, May 1831. • 



ON OXALIC ACID. BY M. GAY-LUSSAC. 

 I was aware with all chemists, that oxalic acid when heated is 

 partly volatilized, and that the remainder is decomposed, yielding 

 a mixture of carbonic acid and an inflammable gas*. As I was de- 

 sirous of knowing more particularly the nature of the inflammable 

 gas, I put some very pure crystals of this acid into a glass retort, 

 which was gradually heated. At SOS'-' Fahrenheit, the acid was 

 completel)' fused; at 230° an elastic fluid was disengaged with the 

 vapour of water ; the volume of gas gradually increased as the tem- 

 perature of the acid rose by the loss of the water of crystallization ; 

 from SiS^ to 266^ the evolution of gas was extremely rapid, and 

 it continued until the oxalic acid was completely decomposed, but 

 with some variations of temperature, which were not precisely 

 noted. 



This ready decomposition of oxalic acid, by a very moderate heat, 

 is the more remarkable, because unforeseen, and because the 

 oxalic acid is considered as one of the most stable of the vegetable 

 acids. Its decomposition by concentrated sulphuric acid, into equal 

 volumes of carbonic acid and oxide of carbon, is not opposed to 

 this opinion, and is readily explained by the powerful affinity of 

 sulpiiuric acid for water, in consequence of which it destroys and 

 carbonizes a great number of organic vegetable substances. 



The examination of the elastic fluids, obtained by the decompo- 

 sition of oxalic acid, has shown me that they are very nearly a 

 mixture of 6 parts of carbonic acid gas, and 5 of oxide of carbon. 

 These proportions varied but little in the course of the operation, 

 yet towards the end the proportion of carbonic acid was rather 

 larger. 



The decomposition of the oxalic acid by a moderate heat made 

 me suspect the intervention of sulphuric acid. 1 found, in fact, 

 that in employing tliis acid the oxalic acid began sensibly to de- 

 compose at tlie same temperature as when it was alone ; that is to say, 

 at from 2:50" to 239' of Fahrenheit. IJut an essential difference is, 

 that with sulphuric acid equal volumes of carbonic acid and oxide 

 of carbon are obtained, as Doberciner has observed, while oxalic 

 acid alone gives the same gases in the proportions of (J to ;'). 



This dilfurence led me to think, that during the decomposition of 

 oxalic acid, without the presence of sulphuric acid, another com- 

 pound must be formed to explain the loss sustained of oxide of 



• See Phil. Waj;. and Annals, N.S. vol. ix. p. 1(51. — Eurr. 

 N.i^. Vol.10. No. 56. Aug. 1831. X carbon 



