338 Transactions of the Canadian Institute. [Vol. VII. 



Smith gives : — 



London, 1869, chlorides 1.2 grams ; sulphates 16.45 grams per million. 

 Glasgow," " 8.97 " " 70.19 " " " 



Ad. Bobierre (Smith, 1872), gives : — 



Nantes, ammonia 1.997 grams per cubic meter, 

 salt 13.9 " " " 



M. Bobinet (Smith, 1872), gives: — 



Paris, calcium sulphate 20 grams per million. 



According to Smith the sul[)hates foimd in the air are alkaline 

 sulphates, and these sulphates are largely the product of organic 

 decomposition. On a complete analysis he found that a hectare of land 

 at Caen received in rain-fall in one year : — 



NaCl 37-5 kilograms. 



KCl 8.2 



MgCl, 2.5 



CaCU 1.8 



Na„SO^ 8.4 



K^SO^ , 8.0 



MgSO^.. 6.2 



CaSO, 5.9 



and besides these he found ammonium salts, iron oxide, and oxide of 

 manganese and nitric acid. 



From this it may be seen that rain-water is an excellent nutrient 

 solution in a very dilute form and it is extremely probable that some of 

 the food substances of the plant are obtained directly from this source. 



One important conclusion may be drawn from the experiments 

 described in this chapter. Since growth of plants is dependent for 

 energy upon destructive metabolism, and since destructive metabolism 

 is (for aerobic plants) dependent upon the absorption of free oxygen 

 (Vines, p. 332), it follows that because oxidation of iron is hastened in 

 an atmosphere under the influence of sea-water, growth may be hastened 

 by a similar chemical process. What applies to the destructive 

 metabolism of plants applies in a large measure to the same process in 

 animal life. 



