20 



earth loose, for the free admission, and circulation of 

 air and moisture, and thus by their chymical combi- 

 nation promotes the growth, and forms the substances 

 of plants and trees ; hence the reason why animal 

 substances produce the best effects in the promotion of 

 vegetation, because they cause the greatest degrees 

 of fermentation, in their dissolution ; and hence the rea- 

 son why the growth of trees and plants never exhausts, 

 or diminishes, the weight of earth in which they grow. 



Electricity has its full share in producing the 

 above effects, both in the animal and vegetable 

 kingdoms ; but not upon the same principles of oxy- 

 gen, because electricity is the most subtle and 

 powerful of all substances, and pervades with equal 

 ease all bodies, whether hard or soft : not so with 

 oxygen, it cannot commix with the earth, and thus 

 become food for the roots of plants, any further thaa 

 this earth is rendered light, or pervious, for the admis- 

 sion of common air; hence the reason why frequen-t 

 plough ings, and fermenting substances promote ve- 

 getation ; hence the reason why plaster, when mixed 

 with the seeds which are planted in the earth, gives 

 the greatest vigour to vegetation ; because it imparts, 

 both its oxygen, and substance, to the absorbant ves- 

 sels of the roots, and thus stimulates the vital princi- 

 ples of those plants. 



All this is true as far as it goes, and yet all this 

 without the heat of the sun, amounts to nothing ; and 

 all this combined with the heat of the sun, amounts 

 to but very little, without the light of the sun : but 

 the rays of light from the sun are not oxygen, nor elec- 

 tricity, and yet they constitute one of the essential 

 causes of vegetation, yet what effects they produce, 

 and hozo they" produce them, are altogether concealed 

 from our research, therefore ! conclude as before, that 

 one fact in good husbandry is worth two hypo- 

 theses. 



Experience has proved Gypsum to be one of the 

 best manures, and taught us how to use it. 



