374 ESSAYS and OBSERVATIONS? 



iation of nitre with bole ; then we have 

 fome reafon to conclude, that this part 

 of nitre is not a fimple elementary mat- 

 ter : Since fixed nitre can, by frequent fo' 

 lutions and fufions, be fo changed^ that 

 little of it will remain but a mere 

 earth. 



Many of the folutions which happen 

 in chemiftry are of the firfl kind ; that is, 

 the folvents adl no otherways upon their 

 proper objedls than water does upon nitre 

 or any other fait, by diflblving the cohe- 

 hefion of the larger particles which com- 

 pofe the body, without relolving the par- 

 ticles into their primary elements. 



When fpirit of nitre or aquafortis is 

 poured upon pieces of filver, the appear- 

 ances plainly point out that there is art 

 attracflion betwixt the particles of the fol- 

 vent and the filver; and that there is like- 

 wife a repulfion of the particles already 

 diflTolved from the filver, to make way for j 

 the application of new particles of the 

 folvent to other parts of the filver: For 

 there is a remarkable motion and agita- 

 tion in the liquor ; the lurface of the filver 



foon- 



