36S DECOMPOSITION OF CERTAIN SUBSTAls'CEJl BY ilEAT. 



to know exactly the quantity of hidrogetl prfescnt, whlcli, 

 in this residuum, was mingled with a great deal of comriion 

 air, it was burnt in Volta's eudiometer, with kn atdditioft 

 of hidrogen and oxigen iti kndwrt quantities, id Order to 

 render the combustion complete and more easy. 

 Results. Thus we fOund, that in these gasses the ammotiia was to 



the hidrogen as 28 to 23. But as we knew, that thd ifter- 

 cury absorbed 3*47 titries its bulk of hidrogen in ]()assing 

 to the state of soft amalgam, it follows, that, in acquiring 

 this state, it absorbs at the same titil* 4-22 tiifies iH bulk 

 of ainraOulacal gas : and cotisequ eiitly the mferctiry, !tt psii$» 

 Ing to thfe stdte Of amalgam, is ihci-feased in \teight about 

 0-0007; while from the experiments of Mr. Davy it id 

 increased only a t\^el?fe-thOusandth. ,Our increase toO iS k 

 minimum; for it is very possible, that a part of the am- 

 inonia is absorbed in thii course of otir experiment. Though 

 this increase is very small, it would appear sufficient to 

 explain the formation of the amalgam, if it be considered, 

 th^t hidrogen and ammonia are very light substances ; and 

 that, being retained in this amalgam by a very w,eak affinity, 

 they are starcely more condensed than in the free state. 



ti. 



On the Decomposition of some vegetable or animal Subm 

 stances subjected to the Action of Heat : by Mr. Gay- 



LUSSAC*. 



5ortesub- V^ ilEN" certain substances belonging to the vegetable 



decomposed by 01* animal kingdom, as oxalic acid, indigo, &c., are sub- 

 heat, partly jected to distillation, part is decomposed, and part is vola- 

 tilized without alteration. To prove, that this is not owing 

 to the impurity of these substances, we have only io distil 

 anew what was volatized, and we shall find as much in pro- 

 portion decomposed as tbe first time; so that, if the pro- 

 cess be frequently repeated, we shall obtain a complete de- 

 composition. These facts, though very remarkable, Iiav6 



* Ann. cte C^im. vol. Ixxiv, p. 189. Communicated Co vthe 

 Society of Aicueil, Novarabfef, 1809'. 



not 



