57 



attracted their attention. So I attempted to do that 

 one thing, and I am very much gratified indeed that the 

 attempt should have succeeded so well that many have 

 already made some effort in that direction, and some have 

 made a very considerable attempt at demonstrating 

 whether there is anything really good or not in the sug- 

 gestion. The paper I have to present to-night is not very 

 long, and it is in the way of a supplement to the first 

 presentation. 



Sub-watering and Dry Air in Greenhouses* 



BY J. C. ARTHUR, OF THE PURDUE EXPERIMENT STATION. 



The time was when acceptable greenhouse culture 

 called for a maximum growth without close inquiry into 

 the question of healthy and normal development. The 

 ideal of the gardener was a tropical jungle with steaming 

 atmosphere, and a wealth of luscious foliage and flower. 



The use of glass houses for winter production of vege- 

 tables and flowers delighting in cool weather, such as 

 lettuce, radish, rose and carnation, brought with it some 

 modification of the tropical ideal. But doubtless the most 

 potent factor in changing the point of view has been the 

 pressing necessity for protection against the many de- 

 structive parasitic diseases. When the rust, smut, rot or 

 mildew carried off a crop, as it did much oftener and 

 more completely than in the open air, an inquiry into the 

 causes of the epidemic revealed advantages in methods 

 that eliminated the conditions that favored the growth of 

 the fungus as fully as could be done without interfering 

 with the growth of the crop. Incidentally it was learned 

 that the old time notions reg-arding greenhouse methods 



