igoo-i.] Effects of Water on Foliage Leaves. 331 



about half an inch apart, leaving an open ventilating canal in the form 

 of a cross, in order to secure some ventilation and yet to have no direct 

 current of air within the jar. Each jar was removed every two days 

 and sprayed upon the inside from a wash-bottle having a fine nozzle. 

 This spray was of a liquid corresponding to that in the receptacle 

 under the jar: — (i) Sea- water; (2) Salt water; (3) Distilled water. 

 The spraying was done at some distance from the specimens, and in no 

 case was there enough of the spray to cause drops to run down and off 

 the side of the bell-jar. The object of this was to secure a moist 

 atmosphere and to aerate fully. 



There was one very peculiar phenomenon which developed during 

 the experiment and one which is worthy of note. The jar containing 

 the sea water did not become dry on the inside, even after four or five 

 days, while the others dried completely (during the course of the first 

 experiment) in twenty-four hours or less, consequently the jar containing 

 the sea-water was not sprayed as often as the others, although it was 

 the intention, when the experiment was arranged, to spray them all 

 regularly. Why did the jar containing the sea-water remain moist, — 

 the water clinging in small drops — while the others dried so readily ? 

 This phenomenon raises one of the most interesting questions relating 

 to atmospheric conditions, and the effect upon plant and animal life. 

 The experimental work belongs rather to physics and chemistry than to 

 botany, so it will be deemed sufficient to merely answer the question 

 leaving the details to the realm of physics where it belongs. Experi- 

 ments were performed with some solutions, simple and compound, by 

 placing a drop upon a leaf and leaving it undisturbed for several hours, 

 and in some cases for several days, for the purpose of finding out 

 whether the solution was absorbed by the leaf During the performance 

 of this experiment, among other things observed was that certain 

 solutions did not seem to evaporate for some days, while others became 

 dry in from one to six hours. Some solutions remained upon the leaf, 

 having the appearance of a drop of water, for a remarkably long time. 

 The same was then tried with glass plates, instead of leaves, and it was 

 found that similar results were obtained — the same solutions remaining 

 moist. A comparison was then made between glass and leaves and 

 results obtained which showed that the moist condition was kept up 

 longer by those drops which were on the leaves. Certain salts are very 

 hygroscopic in their nature, e.g., magnesium chloride, sodium acetate, 

 etc., and it was these salts which remained longer moist, — retaining not 

 only their necessary water of crystallization, but also enough besides to 

 keep the whole in a liquid form. Certain mixed solutions exhibit this 



