212 Agkicultural Experiment Station, Ithaca, N. Y. 



The figures plainly show: 1. That the electric light did uot 

 determine the periodicity of growth. 2. That increase under the 

 light occurred only during the first days. 3. That growth in 

 both houses took place in daylight as well as in darkness. The 

 conclusions suggested by this short, record, I believe to be generally 

 true of lettuce, when grown under the conditions here present 



SUKMABY. 



1. The influence of the electric arc light upon greenliouse plants 

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

 sition of a glass roof. Plants which are much injured by a nalced 

 light, may be benefited by a protected light. 



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

 when grown in ordinary conditions. 



3. The light can be suspended above the house with good effect. 



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 forty 

 feet, in only diffused light, the effect was marked. The light 

 appeared to injure young newly transplanted plants. 



5. Radishes were also benefited by the light, but not to a great 

 extent. WTien the light was hung in the house, however, whether 

 naked or protected by a globe, radishes were injured. 



6. Beets and spinage appeared to be slightly benefited by the 

 Hght. 



7. Cauliflowers under the light tended to grow taller than in 

 ordinary conditions, and to make fewer and smaller heads. 



8. Violets and daisies bloomed eai'lier in the light house. This 

 corroborates results obtained with other flowers in our earlier 

 experiment. 



9. The electric light does not appear to determine or modify the 

 hours of growth of lettuce and some other plants which have 

 been studied in this particular. Plants which are benefited, 

 simply grow more rapidly during the customai*y periods. 



10. I am convinced that the electric light can be used to advan- 

 tage in the forcing of some plants. 



L. H. BAILEY. 



