300 On the Idejitity of Silex and Oxygen^ 



splendid discoveries, which now, and probably will ever 

 continue to, engross the attention of the scientific world, 

 the decomposition of glass and consequent disposal of all 

 its ingredients, form a question, to nie al least, of the ut'* 

 most interest; since, as far as I can judge of the pheno* 

 mena, which have already been described, there appear cir* 

 cumsiances more likely to confirm, than invalidate, my 

 opinion of the nature of silex. 



There is a remarkable similitude in the effects of oxygen 

 and silex on the metals, particularly in that process called 

 vitrifcatio??, which is, in every meaning of the word, a 

 coniplete saturation. By means, of these, particularly the 

 silex, all the metals, perhaps, with no exception, from 

 being the most opaque bodies in the universe, may be ren<» 

 dered quite pellucid, affording an endless variety of the most 

 charming tints, as useful as they arc elegant, smce it is chief- 

 ly from metals and metallic. substances that the most durable 

 and valuable colours arc obtained for staining glass and mak- 

 ing artificial gems. The best op.ike colours, such as are most 

 suitable for enamel, water, oil, crayon, and all other descrip- 

 tions of painting, are derived also from the metals, combined 

 with one or both of these substances ; and though alumine 

 and other bodies are occasionally present, they are as ofter^ 

 absent. Even the precious stones and the less valuable peb- 

 bles, spars, and an infinite list of fossil productions, seem 

 to derive their intrinsic value, beauty and other excellen- 

 cies, entirely from the power of silex on the metals. Thus, 

 the dull opacity of lead is as effectually changed by the sand, 

 used in the composition of flint-glass, and the whole com- 

 pound appears not less diaphanous, than the very same metal 

 is, when, by means oi oxygen ^ it is dissolved in nitric acid, 

 properly diluted with water ; such, however, is the infe- 

 rence I would draw from these premises. 



The near connection between potash and silex, is not less 

 manifest than in the other associations which have been 

 already noticed ; indeed, seeing with what avidity the base 

 of potash (according to the late discoveries) clings to oxy- 

 gen, I am furnished with this plea, that its original and 

 necessary quantity had been obtained from silex ; for all the 



potash 



