PLANT PHYSIOLOGY 17 



and experiments have recently been performed in 

 Norway, Switzerland, and other countries for manu- 

 facturing nitrate of lime and nitric acid fr6m the 

 atmosphere by means of electricity. Prof. J. J. 

 Thomson says that "the extraction of nitric acid 

 from the atmosphere cannot be done in England 

 because power is too dear. It is only when you 

 get very cheap water power that it is possible. 

 The manufacture is quite feasible if you can get 

 power cheap enough." 



The artificial production of nitrates will render 

 an enormous service to horticulture, as well as to 

 agriculture. 



Mineral or Ash Constituents are essential for 

 the growth and development of all plants, and trees 

 are no exception to the rule. These mineral sub- 

 stances must be supplied to all cultivated soils, in 

 the form of manures ; if not the tree is incapable of 

 yielding a full crop of fruit, or produces poor 

 flowers and foliage — in fact the tree or plant 

 degenerates. 



Plant Circulation. — Major (1639-1693) is gene- 

 rally regarded as the father of circulation in plants 

 (a subject by no means beyond dispute still), but 



Nature's resources, properly utilised, are ample. Instead of being 

 satisfied with an average world-yield of 12'7 bushels an acre, a 

 moderate dressing of chemdcal manure would pull up the average to 

 twenty bushels — thus postponing the day of dearth." 



