324? NATURE AND DECOMPOSITION OF THE FIXED ALKALIS?.- 



voured to show*, may contain both saline and metallic im- 

 pregnations ; and the free atmosphere almost constantly 

 holds in mechanical suspension solid substances of various 

 kinds. 

 All the pro- In the common processes of nature, all the products of 



beines°nia'y'be ^'^^"§ beings may be easily conceived to be elicited fronx 

 elicited from knowtt combinations of matter. The compounds of iron, 

 nations.*^"'" '" ®^ *^® alkalis, and earths, with mineral acids, generally 

 abound in soils. From the decomposition of basaltic, por- 

 phyritic +, and granitic rocks, there is a constant supply 

 of earthy, alkaline, and ferruginous materials to the sur- 

 face of the earth. In the sap of all plants, that have beea 

 examined, certain neutrosaline compounds,, containing pot- 

 ash, or soda, or iron, have been found. From plants they 

 Organization may be supplied to animals. And the chemical tendency 

 than "^decompo- ^'^ organization seems to be rather to combine substances 

 ses. into more complicated and diversified arrangements^ than tc 



reduce them into simple elements. 



VIII. On the Nature of Ammonia and alkaline Bodies irt 



general; with Observations on some Prospects of Disco.^ 



very offered by the preceding Facts. 



Composition of Ammonia is a substance, the chemical composition of 



ammonia sup- .^l^j^jj ^^^ always been considered of late years as most per- 



certained. fectly ascertained, and the apparent conversion of it into 



hidrogen and nitrogen, in the experiments of Scheele, 



Priestley, and the more refined and accurate experiments of 



Berthollet, had left no doubt of its nature in the minds of 



the most enlightened chemists. 



* Bakerian Lecture, 1806, page 8. 



f In the year 1804, for a particular purpose of geological in« 

 quiry, I made an analysis of the porcelain clay of St. Stevens, in 

 Cornwall, which results from the decomposition of the feldspar ot 

 fine-grained granite. I could not detect in it the smallest quantity 

 of alkali. In making some experiments on specimens of the un- 

 decompoimded rock taken from beneath the surface, there were 

 evident indications of the presence of a fixed alkali, which seemed 

 to be potash. So that it is very probably, that the decomposition 

 depends on the operation of water and the carbonic acid of the at- 

 mosphere on the alkali forming a constituent part of the chrystal- 

 line matter of the feldspa;-; which may disintegrate from being de- 

 prived of it. 



■^ A13 



