MR. NICHOLS' ADDRESS. 7 



If you procure from one of our hills apiece of granite of either of 

 the different varieties, and finely pulverize it and analyze it, you 

 will find it to contain all the constituent elements of which all other 

 rocks consist. Hence, you will be led to conclude, that they all 

 originate from the granite, that this is the parent rock of quartz, 

 talc, serpentine, feldspar, mica, &c., from the crumbling of which 

 our soils have been formed. By the decomposition and crumbling 

 of the mica and feldspar in a particular region, one kind of soil is 

 formed ; by limestone in other localities, another kind ; and hence, 

 it is plain to see that a variety of soils must result from the disin- 

 tegration of the different kinds of rocks. A very clear conception 

 of the work of exfoliation, may be obtained, by supposing an indi- 

 vidual to have been placed upon our planet at a time wben it was a 

 hard impenetrable mass of rock. Suppose him to have lived 

 through all the great epochs of time until the present, and to have 

 witnessed the gradual metamorphosis from barren sterihty, to the 

 extreme of vegetable luxuriance. Suppose him capable of witnes- 

 sing the gradual crumbling of the adamantine masses, and the for- 

 mation of cultivatable soils. If the agencies in past ages were the 

 same as are now at work, he would have seen that every flash of 

 lightning that shot athwart the sky, by decomposing the atmosphere, 

 produced a trace of nitric acid, and that this, falling upon the rock, 

 aided in the work of separation. He would have seen that the 

 carbonic acid of the air, the rapid freezing and thawing, the 

 mechanical effects of rain, the attrition of dust moved by winds, 

 all conspired to reduce the seemingly defiant Quartz, and Talc, 

 and Gneiss, to a finely subdivided powder capable of sustain- 

 ing vegetable life. The Chemistry of these atoms of dust is very 

 easily understood. God, in the beginning, made use of about sixty 

 different kinds of materials in constructing our planet, and he select- 

 ed ten or twelve only of thefia, from which to form all kinds of rocks. 

 It follows that the dust atoms must be made up of the same mate- 

 rials as the parent rock. From them the mineral food of plants is 

 obtained. The inorganic, or mineral food, which plants require, 

 are principally SiHca, Lime, Magnesia, Sulphur, Potash, and Soda. 

 Their presence in the soil is indispensable, as without them no 

 plant growth could begin and continue. A plant has as capricious 

 an appetite for its mineral food as a human being has for its food, 



