JtJfALYSfIS OF VECjETABLE AND* ANIMAL SUBSTANCES. JQj 



[I "97 in.] from its aperture. The second is a brass collar, 

 in wlrcli the open end of the lar^ glass tube is fixed by 

 means of a cement, that will not fuse under 40° [104° F.j 

 The third piece is a cock of a peculiar construction, in which 

 all the merit of the apparatus consists. The key of thia 

 cock is solid, and ra<iy be turned into any position, without 

 giving' pass-ag'e to the air; but about the middle of it/i 

 length it has a superticial cavity, -capable of holding a sub- 

 stance the f>ize of a small pea. This cavity is so contrived, 

 that when uppermost it answers to a small vertical funnel, 

 which enters into the nozzle, and forms as it were its ex- 

 tremity ; and when lowermost it communicates with the 

 body of the cock, which is perforated, and screws into the 

 brass collar before mentioned. Thus on putting small 

 fragments of any thing into the funnel, and turning the 

 key, the cavity is filled with them, and conveys them, on 

 continuing to turn it, into the body of the cock, whence they 

 fall into the brass collar, and so to the bottom of the glass 

 tube. 



Tf this matter therefore be a mixture of some vegetable Its applicai^ 

 substance with hyperoximuriate of potash in suitable pre- ^'°"* 

 portion, and if the lower part of the glass tube be suffici- 

 ently hot, it will scarcely touch it before it is vividly in- 

 flamed ; when the vegetable substance will be instantane- 

 ously destroyed, and converted into water and carbonic 

 acid, which may be collected over mercury, with the super- 

 fluous oxigen gas, by tneans of the small lateral tube. 



To perform this operation readily, it is necessary, that preUminart 

 the matter should separate entirely from the cavity, and steps. 

 fall to the bottom of the tube. For this purpose it is to be 

 made into small balls, as will presently be described. It is Preparation of 

 necessary too to inquire, what quantity of hyperoximuriate j*^^^"^^^?"*^^ 

 will be sufficient for burning the vegetable substance com- 

 pletely ; and at least half as much more must be used, that 

 the combustion may be perfect. 



But of all the preliminary steps the most important is the Analysis of 

 analysis of the hyperoximuriate employed, for all the cal- *^* ."^P*'°*'' 

 culations of the experiments are founded in great measure 

 on this analysis. 



AH this being well understood, it will be esisy ^^onceive, 

 F i ho^ 



