60 



W. Wolley upon the influence of atmospheric moisture on 

 the growth of plants, published a few months ago. The 

 work was carried on at Munich in the experimental 

 grounds of the Bavarian Agricultural College. Farm 

 crops growing in the open field, including alfalfa, hairy 

 vetch, barley, flax and potato, were used; and in order to 

 control the amount of moisture in the air the experi- 

 mental plants were covered with small houses, about 

 three feet by six and five feet high, having glass on three 

 sides. These houses were in groups of three, one having 

 air like the outside air, one having it much moister and 

 one much drier. The plants were enclosed and observa- 

 tions taken throughout the whole growing season, the 

 houses being large enough to permit normal develop- 

 ment. The extra moist air was secured by allowing 

 water to drip upon blotting paper, and the extra dry air 

 by using an absorbant like chloride of calcium. The work 

 was well carried out and the results can evidently be ac- 

 cepted with confidence. 



The well established conclusions may be summed up in 

 a few sentences, the details not being especially impor- 

 tant in this connection. It is particularly interesting to 

 learn that the ash content is always greater in plants 

 grown in dry air, and even the dry weight is usually 

 more, which being interpreted, means that in the dry air 

 more water passes up through the plant, bearing with it 

 more food material derived from the soil, and that this 

 induces an increased production of solid matter in the 

 plant. 



All parts of the plant become firmer in dry air, the 

 woody fibers increase in strength, and the cuticle in thick- 

 ness. This ensures a more substantial development, and 



