Cliemkal Philosophy. 9i 



was fully demonstrated, synthetically as well as 

 analytically, in a course of ingenious experiments^ 

 by Dr. Pearson, of London/ 



Since the commencement of the eighteenth cen- 

 tury, a number of new?;z6'^fl!/^have been discovered, 

 and the affinities and other properties of metallic 

 substances in general have been better understood 

 than before. Those who most eminently dis- 

 tinguished themselves in this department of che- 

 mistry, were Margraaf, Cronstedt, Klap- 



ROTH, SCHEELE, BeRGMAN, VaUQUELIN, KiRWAN, 



Proust, Sage, and Lavoisier; to which might be 

 added many other names. New earths have been 

 discovered, and their chemical properties ascer- 

 tained, by several of the able chemists last men- 

 tioned, and also by Black, Gahn, Hope, Craw- 

 ford, and Wedgewood. That class of chemical 

 substances denominated alkalies, has been better 

 understood, of late years, than in the preceding 

 century. For our knowledge of this department 

 of the science in question we are particularly in- 

 debted to the investigations of Du Hamel, Black^ 

 Meyer, Priestley, Dieman, VanTroostwyck^ 

 BoNDT, Berthollet, and Austin. Modern che- 

 mists have also discovered many new acids, and 

 thrown much new light on the nature and princi- 

 ples of acidity. Lavoisier first proved that ary- 

 gen, united to certain bases, formed acids: he 

 therefore concluded that this substance is the great 

 acidifying principle ; and showed, by a number of 

 ingenious and accurate experiments, that when it 

 is taken away, the base from which it is separated 

 loses its acid properties. The most distinguished 

 discoverers of new acids, and of new properties 

 in those before known, were Macquer, Sau- 

 VAGEs, Margraaf, Bergman, Keir, Lowitz, 



a Philosol>hical Trarrtadmi for 1793. 

 O 



