172 The Scottish Naturalist. 



twigs of a thick forest of arboraceous plants ; then again as an 

 iron carbonate slowly accumulating at the bottom of a morass 

 of the coal measures ; then as a layer of indurated bands and 

 nodules of brown ore underlying a seam of coal ; and then, 

 finally, that it should have been dug out, and smelted, and 

 fashioned, and employed for the purpose of handicraft, and yet 

 occupy, even at this stage, merely a middle place between the 

 transmigrations which have passed, and the changes that are 

 yet to come." 



As with iron, so with most other substances, dissemination, 

 combination, change, has been the perpetual order of all 

 material things. Upon these mechanical and chemical laws ol 

 change the vegetable, and hence the animal kingdom, has 

 depended. Had not the denuding agencies laboured to 

 destroy, and the mechanical distribution of the debris been 

 effected, the world would have remained a bleak and barren 

 wilderness of rugged rocks ; but " Nature is but a name for an 

 effect whose cause is God," and so the hardest rocks have 

 yielded to the influences that the Almighty Creator fore- 

 ordained, and their ruins are spread abroad upon the earth, 

 and the world is fitted for vegetable existence. Barren spots 

 are greatly the exception, and places utterly void of animal and 

 vegetable life are very rarely met with. 



If the general ideas of less than forty years ago were correct, 

 that plants derived their nutriment from pre-existing vegetable 

 matter, it were then necessary that all soils should contain a 

 large proportion of carbonaceous and other constituents of 

 vegetables ; but this is found to be not at all necessary, indeed, 

 where the soil contains any such carbonaceous material it has 

 invariably been derived' from vegetable growth, and where 

 vegetation is growing upon such humus the carbonaceous 

 matter is proportionably increasing. It is not necessary in 

 some cases that any such vegetable materialjshould exist in the 

 soil. Plants have been grown in soils from which all organic 

 carbonaceous matter has been purposely expelled with perfect 

 success, and crops are abundantly reared upon natural soils in 

 which no vegetable material exists — indeed some plants grow 

 best upon such soils. " According to Darwin, rich harvests of 

 maize are yielded in the interior of Chili and Peru by soils 

 consisting of the merest quicksand never enriched by manure. 

 According to Colonel Campbell, the soil of the cinnamon 

 gardens at Colombo, and where else the tree is cultivated, is 



