Intelligence and Miscellaneous Articles. 77 



of azote ; and in this case it is evident that the hydrogen of the sul- 

 phuretted hydrogen is derived from the water. But to have a more 

 direct proof of it^ I prepared some sulphuret of calcium^ to which I 

 afterwards added some sulphur and water, and 1 subjected them to 

 the action of heat : sulphuretted hydrogen was plentifullye volved. 

 I obtained the same result by heating moistened sulphuret of barium 

 without the addition of sulphur, or rather, by passing the vapour of 

 water over tlie sulphuret heated to redness, because this sulphuret 

 contains three proportions of sulphur ; but with the sulphuret of 

 calcium, which contains only one proportion, the addition of sulphur 

 is requisite. Without this addition water is not decomposed 3 the 

 assistance of double affinity is necessary. 



It results from these observations, that during the preparation of 

 Boyle's fuming liquor, a portion of the sulphuretted hydrogen is un- 

 questionably produced by the hydrogen of the muriatic acid of the 

 muriate of ammonia ; but that the water formed at first by the combi- 

 nation of this latter acid with the lime, at a low temperature, may 

 afterwards in part re-act upon the mi.xture of sulphur and sulphuret 

 of calcium, and produce sulphate of lime and sulphuretted hydrogen. 

 It follows also from these observations, that muriate of ammonia may 

 be replaced by another ammoniacal salt, provided it is hydrated, or if 

 it be not, that the action of water should be made to intervene. — 

 Annates de Chim.etdePhys. March, 1829. 



PURIFICATION OF OXIDE OF MANGANESE, BY M. LASSAIGNE. 



Treat the native peroxide of manganese with diluted muriatic acid, 

 in order to dissolve the foreign carbonates ; then boil with it four or 

 five times its weight of concentrated sulphuric acid, and evaporate the 

 resulting mass to dryness j treat this with eight or ten times its weight 

 of boiling water, and the protosulphate of manganese formed will be 

 dissolved ; but the solution contains iron and sometimes copper : the 

 liquor is to be acidulated with sulphuric acid, if not already so, and 

 then sulphuretted hydrogen passed into it throws down the copper 

 in the state of sulphuret, which is to be separated by filtration. When 

 all tlie copper has been thus separated, the liquor is to be boiled, to 

 separate the excess of sulphuretted hydrogen j and then it is to be 

 decomposed by carbonate of soda. 



The yellowish-white precipitate, consisting of the carbonates of 

 manganese and iron, is washed, and then treated hot with excess of 

 solution of oxalic acid : oxalate of manganese results, which is pre- 

 cipitated in a fine white powder ; and soluble oxalate of iron remains, 

 which is separated by repeated washings with hot water. 



The oxalate of manganese thus obtained, furnishes pure protoxide 

 of manganese by calcination in close vessels, and the gaseous pro- 

 ducts are carbonic acid and oxide of carbon, in variable proportions. 

 The ])rotoxide of manganese, prepared in this way, is gray, and 

 slightly greenish ; it is totally soluble in muriatic acid without any 

 disengagement of gas. — Ibid. 



