j^o On the Analyjis and Synthejii 



mixture was brought to a red heat, they obtained, for re* 

 fiduum, carbonate of potafh, lime, magnefia, and even fome 

 alumine. 



Without defcribing all the fruitlefs trials made to find the 

 tlirec earths produced in this experiment, 1 Ihall relate fome 

 of them, which prove that thefe pretended converfions arife 

 onlv from the impurity of the charcoal employed 



Having made choice of light charcoal from white wood, it 

 was pulverized and ftrongly calcined. Sixteen grammes of 

 pure potafh and eight grammes of this calcined charcoal 

 ■were then exatlly mixed, by moiftening it with a little wa- 

 ter; after which it was put into a platina capfule, and 

 brought to a red heat. The refiduum, after being edulco- 

 rated with water, to feparate from it all the potafli, was 

 treated with nitric acid. The folution, when filtered, gave by 

 evaporation a glutinous matter, found to be filex. The ni- 

 trates feparated from this filex gave lime and magnefia. 



Prefumin<T that the charcoal mioht be the caufe of the 

 prefence of the hmc and magnefia found in this experuiienr, 

 I thought it my duty to alfure myfelf of it by analyfing that 

 employed. 



I burnt ai6 parts of the fame charcoal to reduce it to 

 afhes, taking care to employ a platina crucible; the aflies 

 obtained weighed only 91 parts. This refiduum Was treated 

 with the nitric acid. By proper evaporations, the prefence of a 

 great deal ©f carbonate and fulphaie of lime was afcertained. 

 The products obtained feparately by the common jjrocelfeS 

 gave filex 41, magnefia 16, lime 12, alumine 3. 



For the fake of greater precifion, and to be more fully con- 

 vinced in reoard to the exillence of lime in the charcoal, as 

 Well as to prove that the lime found hv C. Dcformes arole 

 onlv from the charcoal employed, I made the following ex- 

 periment : 



I took four grammes of pure charcoal obtained from the 

 decompofition of the carbonic acid by phofphorus, and, hav- 

 ing mixed it with 18 grammes of pure potafii, put it into a 

 platina capfule, and brought it to a red heat, having pre- 

 vioufly taken care to moiUen it. The matter which thence 

 refulted being treated with water, there remained a black re- 

 fiduum, which was treated with nitric acid, and the iolutior^ 

 diluted with water was filtered. This nitric folution was 

 mixed with oxalate of ammonia; but this fait produced no 

 alteration in the above liquor, even when the excels of acid 

 v;as faturated by ammonia ; which it could not have failed to 

 <lo had there been ever fo little lime, or even magnefia and 

 alumine. This would. be tlie place for calling the reader's 



attention 



