220 Notice of some Recent 



My analyses of ammoniuret of mercury agree closely with 

 that of Guibourt ; but dried at a moderate heat, I have 

 found it to contain much water, which he does not mention 

 as a constituent. Its formula is (3 Hg + 2 N H 3 + 4 H) 

 or, (2 Hg + 2 N H 2 + Hg) + 6 H), if we suppose the 

 ammonia to exist as amidogene, which is almost proved by 

 the composition of the chlorides of mercury compounds. 



I expect to find still more remarkable examples among 

 the compounds of those metals with small atomic weights. 

 The large quantity of mercury in the bodies above described 

 renders the differences in the proportions of the other in- 

 gredients too small to be decisive crucial instances. 



Another subject on which I have got some interesting 

 results is the action of Muriatic Acid on some oxygen salts. 

 The sulphates are those I have most examined as yet. Dry 

 muriatic acid gas is not absorbed by the sulphates of potash, 

 soda, zinc, or magnesia ; but sulphate of copper absorbs one 

 atom, and the sulphates of zinc and mercury about half an 

 atom each. The compound S + Cu) + CI H is brown, 

 absorbs water rapidly, and gives, by crystallization, chlo- 

 ride of copper, all the sulphuric acid remaining in the 

 liquor. The action of liquid muriatic acid is also interest- 

 ing, it expels all the sulphuric acid from bluestone, form- 

 ing chloride of copper. It takes half the base from the 

 sulphates of potash and soda, and hence, in the latter 

 case the large quantity of suddenly liquified water, which 

 gives to that re-action the power of acting as a freezing 

 mixture. 



The results, of which the above are but a few, have led 

 me to a means of examining how far solution is accom- 

 panied by chemical decomposition, a subject on which I am 

 just now engaged. 



Article VII. 

 Notice of some Recent Improvements in Science. 



HEAT AND LIGHT. 



1. Temperature of the Globe. — M. Poisson, in his elaborate 

 work entitled Mathematical Theory of Heat, has broached 



