152 THE ART OF CULTURE. 



soil the red-beech, the service-tree, and the wild- 

 cherry, for example, thriving luxuriantly on lime- 

 stone, we may be assured that alkalies are present 

 in the soil, for they are necessary to their existence. 

 Can we, then, regard it as remarkable, that such 

 trees should thrive in America, on those spots on 

 which forests of pines which have grown and col- 

 lected alkalies for centuries, have been burnt, and 

 to which the alkalies are thus at once restored ; or 

 that the Spartiwn scoparium, Erysimum latifolium, 

 Blitum capitatum, Senecio viscosus, plants remark- 

 able for the quantity of alkalies contained in their 

 ashes, should grow with the greatest luxuriance on 

 the localities of conflagrations.* 



Wheat will not grow on a soil which has produced 

 wormwood, and, vice versa, wormwood does not 

 thrive where wheat has grown, because they are 

 mutually prejudicial by appropriating the alkalies 

 of the soil. 



One hundred parts of the stalks of wheat yield 

 15*5 parts of ashes (H. Davy] ; the same quantity of 

 the dry stalks of barley, 8' 54 parts (Schroder) ; and 

 one hundred parts of the stalks of oats, only 4*42 ; 

 the ashes of all these are of the same composition. 



We have in these facts a clear proof of what 



* After the great fire in London, large quantities of the En/simum 

 latifolium were observed growing on the spots where a fire had taken 

 place. On a similar occasion, the BHtum capitatnm was seen at Copen- 

 hagen, the Senecio viacosus in Nassau, and the Spartium scoparium in 

 Languedoc. After the burnings of forests of pines in North America 

 poplars grew on the same soil. (Franklin.} 



