274 On the Identity of Sllex and Oxijgen, 



onie pound weight,) as that, during its progress through a 

 given space, its force shall be constantly increasing, and 

 thereby produce an accelerated motion exceeding that oi 

 the moving power at least ten to one ? 



I am, sir, your very humble servant, 



Bracknell, Berks, £. VlDAU 



March 22, 1808. 



LIV. 0?i the Identity of Silex and Oxygen, By 

 Mr, Hume, ff Long- Acre, London, 



[Conlinuedfrom p. 17I.J 



To Mr, Tillock, . 



SIR, 



JLiixME., in xU general attractions, aud in its capacity to 



neutralize acids, possesses a very superior energy to clay, 

 and, therefore, is a more decided salifiable base : hence, I' 

 shall give it the preference in any example, in which an 

 car,th, as belonging to a distinct genus, is to be contrasted 

 with silex, whose habitudes and character are so totally dis- 

 similar. 



Nothing is so frequent in nature as an association of two 

 or more contending elements to form one homogeneous 

 compound, or to effect some material purpose : thus, an acid 

 with an alkali, sulphur with a metal, and metals with earths, 

 niay be adduced as instances, in which this coexistence of 

 opposites is, perhaps, as essential as two contrary poles to 

 the same magnet, or the negative and positive wires af the 

 Voltaic pile. This proximity is no where more -obvious and 

 frequent than in substances composed of silex and lime, in 

 which the caustic pungency and other inherent distinctions 

 of the lime are coerced into such a state of neutrality, as to- 

 evade every mode of detection, unless the purity of the com- 

 pound be destroyed and the lime eliminated. 



Silex is not only found alone with lime, but follows it 

 throughout, and in nearly all its modifications; and, gene- 

 rally speaking, this seems the primary cause of the saturated 

 condition of lime in all the native carbonates, such as in 



chalky 



