18 Sketch of the Improvements in Science [5 as, 



sufficiently expressive to answer the purpose. They might be called 

 subbinitrate, siibtrimtrale, subhexnitrate. The prefix stib denoting 

 the duplication of the base, while the numerals denote the number 

 of proportions of oxide in the salt. 



3. Chevreul has described two nitrates of lead, which he obtained 

 by digesting lead in a solution of nitrate of lead. The first is 

 composed of 100 acid + 450 yellow oxide; the second, of 100 

 acid + 910 yellow oxide : or the second is a subbinitrite. 



4. Mr. Wilson, of Dublin, has described a new compound salt, 

 which crystallizes spontaneously in the residual liquor after the dis- 

 tillation of a mixture of 3 parts common salt, 1 part black oxide of 

 manganese, and 4 parts sulphuric acid, of the specific gravity 

 1 500, in an iron still with a leaden cover. The salt crystallises in 

 octahedrons, is neutral, and is decomposed by solution in water. 

 According to Mr. Wilson's analysis, its constituents are as follows : 



Sulphate of soda 55*47 



JNIuriate of manganese 26*79 



Muriate of lead 1-52 



Water 1622 



100-00 



There is something problematic about this salt. Hence it would 

 be desirable that it underwent a further examination. The quantity 

 of muriate of lead is so small (not amounting to an atom) that we 

 can scarcely hesitate to consider it as mechanically mixed. The 

 form of the salt iijdicatos a peculiar species. We know at present 

 very ftw instances of two neutral salts, with different acids and 

 bases, combining together ; yet such a combination seems to take 

 place here ; for the salt in question must consist of a combination 

 of sulphate of soda with muriate of manganese. This combination 

 seems to exclude a great part of the usual water of crystallization 

 of these salts ; for both sulphate of soda and muriate of manganese 

 are remarkable for the great quantity of water of crystallization 

 which they contain.* 



o. Chevreul has examined t1ie sulphite of copper, which is a red 

 crystalliziible salt, composed, according to hii analysis, of 



Red oxide of copper 63*84 



Sulphurous acid 36*16 



10000 



He obtained also a triple sulphite of potash-and-copper, com- 

 posed of 



• Mr. Wllsnn was so obliging as to ofTer to send me some of (he saU ; but I 

 ytm so uiilHcky j^s Io mislay .ind lose his address, -ivhich prcvenled me from 

 aiibWi-iiu^ liis Ictlcr. If tliis notice should happen lo be peruscd by him, I beg 

 in sny th;it I shmild be much gratified by receiving a specimen, as I wl:h to subject 

 it 10 some further trials. 



