64 MASSACHUSETTS HORTICULTURAL SOCIETY. 



matured before they had attained a normal stature. The next 

 logical step, therefore, was to run the light only a portion of the 

 night, in order that the change from normal conditions should not 

 be too violent. 



The third stage in our experimentation, then, concerned itself 

 with the naked light running the first half of the night. The 

 foliage of radishes was noticeably larger in the electric light house, 

 as it had been before under the modified light, but the tubers were 

 practically the same in both houses, and the date of maturity was 

 the same. Notwithstanding its greatpr size, the foliage in the 

 light house showed some signs of curling. Peas were grown, and 

 in every case they were larger and more fruitful in the dark house. 

 The electric light did not increase the size of leaves, as it did in 

 the radishes. These results, also, are similar to those obtained in 

 previous experiments. 



Lettuce, however, was greatly benefited by the electric light. 

 We had found that under the protected light running all night, 

 lettuce had made a better growth than in normal conditions, but 

 now it showed still greater difference. Three weeks after trans- 

 planting lettuce of equal age upon the benches of the light and 

 dark houses, the plants in the light house were fully 50 per cent 

 in advance of those in the dark house in size, and the color and 

 other character of the plants were fully as good. The plants had 

 received at this time 70J hours of electric light. Just a month 

 later the first heads were sold from the light house, but it was six 

 weeks later when the first heads were sold from the dark house. 

 In other words, the electric light plants were two weeks ahead of 

 the others. This gain had been purchased by 16 If hours of 

 electric light, worth at current prices of street lighting about 

 $7.00. This experiment was repeated by reversing the houses for 

 the purpose of eliminating errors, and the results were essentially 

 the same. Seeds were sown in flats, Feb. 24, 1891. Until March 

 17th, they were grown under ordinary conditions, at which time 

 they were set in their permanent positions in the two compart- 

 ments. We began to pick lettuce from the light house April 30, 

 but the first of equal size from the dark house was obtained May 

 10. The electric light plants were, therefore, upon the benches 

 forty-four days before the first heads were sold. During this 

 time there were twenty nights in which the light did not run, and 

 there had been but eighty-four hours of electric light, worth about 



