Jddttional Notes. 5 1 9 



attempted to combine tliese two methods ; and since that time 

 almost all the great writers on mineralogy have tbllovved his 

 example. 



After the publication of the first regular system of Ltn- 

 N.-Eus, and before the appearance of Cronstedt's great 

 work, several other systematic writers attempted to form dif- 

 ferent arrangements of mineral bodies. Among these, Wol- 

 STERDORF, Cartheuser, and Justi, all of Gei many, de- 

 serve to be mentioned. But none of them retain their repu- 

 tation, amidst the numerous discoveries and improvements, 

 and the incomparably better writers produced in later times. 



Chemical Analysis of Minerals, p. 146. 



The progress which was made in the art of analyzing mi- 

 nerals, in the course of the last thirty years of the ei<^hieenth 

 century, cannot be contemplated without astonlsliment. ^* To 

 separate five or six substances intimately combined together; 

 to exhibit each of them separately ; to ascertain the precise 

 quantity of each; and even to detect the presence and the 

 weight of substances which do not approach ~^~ part of the 

 compound, would, at no very remote period, have been con- 

 sidered as a hopeless, if not an impossible task. Yet all this, 

 by means of the wonderful discoveries and improvements of 

 Margraff, Neumann, Scheele, Bergman, Klap- 

 ROTH, Vauquelin, and others, can now be done with the 

 most rigid accuracy." — Thompson'^' Chc7}iistrj/, vol. iv. 



Crj/siallizatio7i. p. 151. 



The subject of Crystallizatioyi engaged much of the at- 

 tention of chemists and mineralogists during tire eighteenth 

 century. The first attempt to account for this phenomenon, 

 in any manner which deserves the name of philosophical, 

 was by Sir Isaac Newton. He supposed the aggregation 

 which taki?s place in this instance to be produced by the at- 

 traction which he had proved to exist between the particles 

 of all bodies, and which acts as soon as tiiese particles are 

 brought within a certain distance of each other by the eva- 

 poration of the liquid in which they are dissolved. The re- 

 gularity of their figure he explained, by supposing that, while 

 m a state of solution, they were arranged in the liquid in re- 



