136 MEMOIR ON THE SCIENTIFIC CHARACTER 



To fix the particles of minerals on a sappare, in order to 

 subject them to high temperature, Mr. Smithson employed 

 water with gum, as used by Saussure, who invented the 

 method, but he added refractory clay. The particle of 

 mineral was then made to adhere to this clay, a small por- 

 tion of it being for this purpose taken upon the end of a 

 flattened platina wire. 



21. In the 23d volume of the Annals, (p. 100,) we find a 

 paper, by Mr. Smithson, dated, January 2d, 1824, " On some 

 compounds of fluorine." 



In this, he makes the apposite and just remark : that, u a want of due 

 conviction that the materials of the globe, and the products of the labora- 

 tory are the same, that what nature affords spontaneously to men, and 

 what the art of the chemist prepares, differ in no ways but in the sources 

 from whence they are derived, has given to the industry of the collector 

 of mineral bodies, an erroneous direction." 



" What is essential to a knowledge of chemical beings, has been left in 

 neglect ; accidents of small import, often of none, have fixed attention 

 have engrossed it -and a fertile field of discovery has thus remained un- 

 explored, where, otherwise, it would have been exhausted." 



His method of illustrating the character of fluor spar, 

 was by fixing with clay a small piece, on a bit of platinum 

 foil, and holding the latter on a clay support, in the end of 

 a bit of glass tube, and thus subjecting it to the action of 

 the blow-pipe. ' 



The topaz was also assayed, and gave out fluorine or 

 fluoric acid. Smithson expresses his conviction that topaz 

 is a compound of fluate of silicium and fluate of alumina.* 



He also examined kryolite, which had been observed to 

 diminish in fusibility during fusion. 



The result of his experiments were : 1st. That fluorides 

 are in general decomposable by heat, and hence, that " we 

 now have a method of discovering the presence of fluorine." 

 2d. The theory of these decompositions may be obtained 

 by experiment. 



Referring to the minute blow-pipe experiments with 

 which his results had been obtained, he significantly re- 

 marks : 



"There maybe persons, who, measuring the importance of the subject 

 by the magnitude of the object, will cast a supercilious look on this discus- 

 sion ; but the particle and the planet are subject to the same laws, and what 

 is learned upon the one will be known of the other." 



22. In the same volume (xxiii.) of the Annals, p. 115, is 

 a short paper of the same date, (January 2, 1824,) containing 

 An account of an examination of some Egyptian colors. 



* At this day he would probably have substituted the terms fluoride of silicium 

 and ./Zworide of aluminum. 



