Volltext Seite (XML)
5eft. 228. INFLAMMABLE SUBSTANCES, 439 imall quantity of earthy fubfhnce, which all phlogifta ture, forms an union with a greater quantity of it, which- caufes a radiant heat. At this moment the-congruent parts of the combuftihle body are fo much difunited by the ftill ■jncreafing heat, that the empyreal air, continuing to pour upon it in ftrearr.s, attradfs the phlogifton in ftill greater quantities; and hence the moft elaftic fubftance, Light, is -compofed, which, according to the quantity of combujiible ■matters, {hows .various colours. Such is the abftradf of Scheeld’s new ifyftem, taken from that given by Mr. Rufiel, in his Notes to Faurcroy's Ledum of Chemiftry, which I compared with the original French tranflation of the Author, as it is more corredt than the ■Englifti tranflation of J. R. Fofter; and it appeared to me perfe&ly confonant to the author’s ideas. But the only fyf- tem that I know, which fully and fatisfaftorily (levelopes thefe obftrufe matters, relating to the nature of ccmbufiible and phlogijiic procejfes, is that given to the public by Dr. Adair Crawford, whofe friendfiiip I {hall ahvayc acknowledge with the higheft pleafure. His New Theory was compleated, and put in the hands of the public, before cither he, or any other perfon in England, had the lettft knowledge of Mr, Scheele’s do&rine. J publiflietj, in the year 1780, a fmall effay on this fubjeff, containing a {ketch of Dr. Crawford’s doftrine, reduced into a mathematical form, which is men* tioncd by the late famous Profeflor Bergman, in his ex cellent treatife de Attradionibus dcdivis, and was inferted in Journal de Phyftque, for May and June, 1781. The follow ing iketch of the part relating to combujiiblej, is the only one ■that can be allowed to this note. Dr. Crawford difcovered, by the moft accurate and nice .experiments, that bodies, which contain a large portion of . PjiOgiJlon, poflefs but a fmall (hare of fpecijic beat or fire; on the contrary, that thofc with a great (hare of this laft, con tain but little phlogijlon; and finally, thofe which are de prived of phlcgtjlon, increafe their capacity for a greater (hare of fpecijic fire. Thus, when regulus of antimony is deprived of-its phlogifton, by calcination, which is then called diapbo- F f 4 retie,
