TOMATO LEAF-MOLD 



19 



PLATE II 



:-^t I 



*5 



(A) Electric Hot Plate with Asbestos Mat and Evaporating Dish Assembled for 



Vaporizing Sulfur; (B) Vaporizing Equipment in Operation in Tomato Greenhouse, 



and (C) in Rose Greenhouse; (D) Sulfur Vaporizer Constructed to Provide Addition 



of Steam Blasts to Molten Sulfur. 



Mass. At Melrose, No. 1 house has a volume of 10,980, No. 2, 37,800, and 

 No. 3, 68,800 cubic feet. At AV^altham, No. 7 house has a volume of 10,000, 

 and No. 3, 5,000 cubic feet. Sulfur was vaporized on electric heating units 

 by the method described. The work was done in the evening and all the 

 ventilators were closed for the night to confine the vapors and permit them to 

 settle naturally. The heating units were operated for two to four hours at a 

 time and disconnected when the vapors in the air were quite dense. Counts 

 were made of the leaf prunings to determine the degree of control, and on 

 the last count the plants were stripped of the remaining leaves. This metliod 

 proved most satisfactory for ascertaining the value of the treatment. 



Spring Crop at Melrose, 1926. Sulfur was vaporized 16 times with 5 stoves 



