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



INTRODUCTION. 



Since so many questions, relating more or less directly to the main 

 one, are involved in the progress of the proper discussion of the chief 

 subject, and since the field is so very broad, it became necessary to 

 select from the very large number of experiments involved, those which 

 seemed to tend more directly towards a full development of the subject. 

 As the main question is an investigation into the effect of certain 

 solutions of inorganic salts upon foliage leaves, and, as the intelligent 

 answer to this question depends so largely upon the capability of leaves 

 to absorb water and the more dilute solutions, e.g., rain water, soil water 

 and spring water, it was found necessary to investigate the matter of 

 the absorption of water and aqueous vapour by leaves. This naturally 

 led to a consideration of the atmospheric conditions which might, 

 through time, give rise by adaptation to certain qualities which leaves 

 may have acquired through ages past. Enquiry was made at the 

 Weather Bureau at Washington, to learn to what extent inorganic salts 

 were known to pervade the atmosphere, either in the neighbourhood 

 of the sea or inland, but it was found that, so far as America was 

 concerned, no work of any importance had up to the present been done. 

 The investigations made in Europe were too general in character to 

 apply directly to the subject under djscussion. This made it necessary 

 to investigate the matter experimental!}-, and a series of experiments 

 was performed to ascertain if the salts of the .sea did permeate the 

 atmosphere without the aid of spray or winds. These experiments 

 are described in detail further on. 



Investigation was also made into the question suggested by a 

 statement of Sachs, that distilled water which remains upon a leaf of a 

 plant becomes alkaline. 



Plants adapted to a moist climate were selected and arranged as 

 shown in Fig. 7, the roots being supplied with nothing but distilled 

 sterilized water and air, while the leaves were fed with a nutrient 

 solution furnished by means of an intermittent spray. Composition 

 of the nutrient solution: — H. O, looo.o grams; KNO3 i.O grams; 

 MgSOi .5 grams; CaSO, .5 grams; K3 PO 4 .5 grams ; FeS04 .01 

 grams. The object of this experiment was to determine whether a 

 plant could use a nutrient solution so applied. On account of the long 



