Intelligence and Miscellaneous Articles. 15 



Columbic acid 82-98 



Oxide of tin 1-21 



Oxide of iron 14'62 



Oxide of manganese .... traces 



SiUca -42 



99-23 



Its composition is therefore similar to that of the mineral from 

 Finland, — Comptes Rendus, Novembre 1847. 



ON THE ACIDS OF SULPHUR. BY MM. FORDOS AND GELIS. 



All the chlorides of sulphur yield, with the aqueous solution of 

 sulphurous acid, the same compounds. The principal product of 

 this reaction is a new oxygenated compound of sulphur, in which 

 live equivalents of sulphur are combined with an equal number of 

 equivalents of oxygen, and form a molecule which saturates only one 

 equivalent of base, and which is consequently I'epresented by the 

 formula S^ 0^ MO. 



This acid differs from all the acids of sulphur hitherto known. It 

 is not to be confounded either with that to which M. Wackenroder 

 has assigned the same formula, without having analysed it, the for- 

 mation of which he observed during the reaction of hydrosulphuric 

 acid on the aqueous solution of sulphurous acid ; for M. Wackenroder 

 states positively, in his memoir, that the barytic salt which he ob- 

 tained is soluble in alcohol and in aether, and is not precipitable from 

 its solution in water by them, whereas it is by these very means that 

 MM. Fordos and Gelis isolate their acid. 



The new acid S^O^, MO is the isomeric of hyposulphurous acid 

 S- 0-, MO. Both have the same composition in 100 parts, but they 

 differ completely in all their characters. Mineral chemistry does 

 not present any case of isomerism comparable to that of these two 

 acids. To discover analogous cases, the compounds of carbon must 

 be referred to ; and this fact supports the approximation, which M. 

 Berzelius was the first to establish, between the composition of the 

 acids of sulphur recently discovered, and that of the compounds of 

 organic chemistry. 



'I'he authors divide all the acids of sulphur into two perfectly 

 distinct classes : in one the sulphur remains invariable, and the 

 quantity of oxygen increases ; in the other, the number of equiva- 

 lents of oxygen remaining five, the sulphur varies as the numbers 

 2, 3, 4 and 5. The acid now particularly described is the last of 

 this class. 



The name of sulphuric series is given to the first : it includes all 

 the acids anciently known ; and the name oithionic series, from Qeloy, 

 sulphur, is given to the four acids more recently discovered. They 

 are distinguished from each other by prefixing to the generic name 

 the Greek particles which represent tlie numbers 2, 3, 4 and 5. 



Thus we have the following acids : — 



Dithionic IS-'O', hyposulphuric acid of Gay-Lussac and Welter. 



