566 Intelligence and Miscellaneous Articles. 



cles. The crystallized sulphate of copper so obtained is often largely- 

 contaminated with sulphate of zinc, which may sometimes be seen 

 in the form of slender white needles on the surface of the dark blue 

 crystals, and in some of the applications of this salt may prove in- 

 jurious. Sulphate of nickel, sulphate of lead, arsenic, and chlorides 

 are also sometimes present. — From the Proceedings of the Chemical 

 Society. 



ON A NEW EUDIOMETRIC PROCESS. BY PROF. GRAHAM. 



Professor Graham described a new eudiometric process for the 

 rapid absorption of oxygen gas from atmospheric air and other 

 gaseous mixtures containing oxygen. It consists in the employ- 

 ment of a solution in ammonia of a sulphite of the suboxide of cop- 

 per and ammonia. This salt falls as a granular powder, when a 

 stream of sulphurous acid gas is conveyed into a cold solution of the 

 ammoniacal sulphate of copper. When dissolved in ammonia it 

 absorbs oxygen with singular avidity, and when employed in this 

 form in eudiometry gives results of considerable uniformity. — From 

 the Proceedings of the Chemical Society. 



EQUIVALENT OF CHLORINE. 



M. Gerhardt observes, that M. Marignac has made some observa- 

 tions and experiments tending to show that the atomic weight of 

 chlorine is not thirty-six times that of hydrogen, as he (M. Gerhardt) 

 had concluded, but somewhat less. M. Marignac's conclusions are 

 derived from the weight of chloride of potassium yielded by the cal- 

 cination of chlorate of potash ; to these results M. Gerhardt makes 

 the following objections : — 



It is the residue of chloride of potassium obtained, and not that 

 of the oxygen gas, which is weighed ; and from the following causes 

 the quantity of chloride might be too small, and would diminish the 

 atomic weight of chlorine :— a trace of moisture on the salt ; a por- 

 tion of chlorate or chloride carried off by the current of oxygen gas ; 

 if the oxygen were impure, and contained, as M. Marignac has 

 stated, a trace of chlorine. 



Thus, observes M. Gerhardt, all the errors which can be com- 

 mitted in these determinations are referrible to the chlorine, and 

 give it in too small quantity. 



From his experiments M. Gerhardt concludes, in opposition to 

 those of M. Marignac, that the equivalents of chlorine, silver and 

 potassium, are exact multiples of the equivalent of hydrogen, that is 

 to say, — 



Chlorine 36 



Silver 108 



Potassium 39 



Journ. de Pharm. et de Ch., Avril 1846. 



