SILEX. 109 



ON SILEX. 



Silex, or pure flint, is the next constituent of 

 vegetable matter to be explained. 



It may seem to those whose attention has 

 never been called to the structure and consti- 

 tuents of plants, that the presence of this sub- 

 stance is impossible ; but yet the analysis of 

 wheat straw, which yields upwards of 60 per 

 cent., (the remaining 40 parts consisting of car- 

 bonate of lime (chalk,) phosphate of lime, 

 potash, or soda and iron) prove beyond all ques- 

 tion its presence; and the mode which nature 

 in her vast laboratory employs for the assimila- 

 tion of this substance, will, therefore, be our 

 next consideration. 



Silex, in its pure state, is perfectly insoluble 

 in water; but silex combined with potash, is 

 perfectly so : indeed, there is a species of glass 

 manufactured from these ingredients, which 

 dissolves perfectly in boiling water. And as 

 potash and silex equally abound in almost every 

 soil, it only remains for us to endeavour to ex- 

 plain how this substance may be formed in na- 

 ture; but this, however desirable, is with our 

 present knowledge unattainable. 



We know that nature has the means in her 

 immense galvanic power, which is constantly 

 in operation, in the powerful auxiliaries that 

 she has in the summer's sun, the winter's frost, 

 and the daily variations of moisture, to reduce 

 the most obdurate substances to a state fitting 

 them for change. And we must be content, at 

 present, with the knowledge that such a power 



