APPENDIX. 673 



monia, which escapes in the gaseous form. At the same time 

 there escapes, (according to the nature of the organic substance,) 

 either pure hydrogen gas, or carburetted hydrogen, which are 

 not absorbed by the acid, and which are easily recognized by 

 burning them with oxygen gas. 



The combustion goes on so rapidly, that a constant current of 

 gas passes off. But there is no risk of any of the ammonia es- 

 caping ; it is absorbed so rapidly and so completely by the mu- 

 riatic acid. When the action of the fire is suddenly stopped, the 

 whole acid liquor gets into the ball a, and it may even (unless 

 care be taken) make its way into the decomposing tube, and de- 

 stroy the analysis. 



But few substances contain so much azote, that, in order to 

 convert the carbon into carbonic acid, the whole hydrogen set 

 free combines with the azote into ammonia. 



To prevent the too rapid absorption of the ammonia, Varren- 

 trapp and Will recommended mixing those substances which con- 

 tain a great deal of azote, with sugar or some organic body des- 

 titute of azote. This last substance, by its decomposition by 

 means of the alkaline hydrate, gives out a permanent gas, which 

 dilutes the ammoniacal gas, and prevents its too rapid absorption. 



When the process is at an end, and this is known by the ceas- 

 ing of the evolution of all gas, and by the substance in the de- 

 composing tube being quite white, the point a of the decompos- 

 ing tube is to be broken off, and air slowly sucked through the 

 apparatus by applying the mouth to the extremity^. The ob- 

 ject of this is to extract any ammonia that may remain and cause 

 it to be absorbed by the muriatic acid. 



The ammonia, while in contact with alcohol and charcoal in 

 the decomposing tube, might form cyanogen or cyanodide of po- 

 tassium. The white appearance of the residue in the decompos- 

 ing tube is a proof that the heat has been sufficient to burn all the 

 carbon, and that the formation of cyanogen is not to be dreaded. 



Such- is the mode of analysis of solid bodies containing azote. 

 The number of organic liquids containing azote is small. The 

 process for analyzing them is quite similar. A portion of the 

 decomposing tube is filled with the mixture of alkaline hydrate 

 and lime, then the glass globule containing the liquid to be ana- 

 lyzed is dropt in, and the tube is filled with mixture of alkaline 

 hydrate and lime. The process of decomposition is the same as 

 before. 



uu 



