234 STUDIES OF NATURE. 



common principles which (he fets a working in 

 our hands, and in our feet. Earth, water, air, and 

 fire, are elements, as we fay. But under what 

 form muft Earth appear, in order to be an ele- 

 ment ? That ftratum called humus^ which almoft 

 every where covers it, and which ferves as a bafis 

 to the vegetable kingdom, is a refufe of all forts 

 of fubftances, of marl, of fand, of clay, of vege- 

 tables» 



Is it the fand which conftitutes it's elementary 

 part ? But fand appears to be a fecretion from the 

 rock. Is it the rock, then, which is an clement ? 

 But it has the appearance, in it's turn, of being an 

 aggregation of fand, as we fee it to be in mafles of 

 free-ftone. Whether of the two, fand or rock, 

 was the principle of the other ? and which took 

 the precedency in the formation of the Globe ? 

 Suppofing us poffefled of authentic information as 

 to this particular, what ground have we gained ? 

 There are rocks formed of aggregations of all 

 foris. Granite is compofed of grains ; marbles 

 and calcareous ftones, of the pafte of (liells and 

 madrepores. There are likewife banks of fand, 

 compofed of the wreck of all ihefe ftones : 1 have 

 feen the fand of cryftal. 



Shell fifh, which feem to give us fome light re- 

 fpeding the nature of calcareous ftone, by no 



means 



