THE HORTICULTURAL SOCIETY OF NEW YORK 



of equal size from the dark house was obtained May loth. The 

 electric light plants were therefore upon the benches 44 days be- 

 fore the first heads were sold. During this time there were 20 

 nights in which the light did not run, and there had been but 84 

 hours of electric light, worth about $3.50. In order to compute 

 the cost of growing lettuce by the aid of the electric light, it is 

 necessary to know how far the influence of the light will extend. 

 This we do not know ; but the lamp exerted this influence through- 

 out a house 20x30, and the results were as well marked in the most 

 remote parts as they were near the lamp. 



"The results obtained from lettuce suggest many questions, all 

 of which must be answered by experiment. We need to know if 

 there is any particular time in the life of the lettuce plant when 

 the light has a predominating influence; if a mild light is as good 

 as a strong one; if the failure of light during the mooi'riight nights 

 is a serious drawback ; to what distance the influence of the light 

 extends ; if the same results can be obtained by hanging the lamp 

 over the house, instead of inside it, and by that means lighting 

 several houses at once ; if other plants can be profitably forced by 

 means of electric light." 



In the third report upon Electro-horticulture in 1893, Dr. Bailey 

 used several varieties of plants and has carefully told us the story 

 of his year's work in the summary of Cornell Bulletin 42 : 



PART PLAYED BY GLASS 



"i. The influence of the electric arc light upon greenhouse 

 plants is greatly modified by the use of a clear glass globe or the 

 interposition of a glass roof. Plants which are much injured by 

 a naked light, may be benefited by a protected light. 



"2. As a rule, plants are earlier under the electric light than 

 when grown in ordinary conditions. 



"3. The light can be suspended above the house with good ef- 

 fect. 



"4. Lettuce is greatly benefited by the electric light. An aver- 

 age of five hours of light per night hastened maturity from a week 

 to ten days at the distance of ten and twelve feet. Even at 40 



32 



