60 MASSACHUSETTS HORTICULTURAL SOCIETY. 



confess that I had expected to be able to reach definite conchisions 

 at the close of the first winter's experiments ; but at the present 

 time, while we are engaged in the fifth annual series of investiga- 

 tions, we find ourselves still very far from definite conclusions 

 concerning some of the primary and fundamental phenomena of 

 the experiments. For four winters we endeavored chiefly to grow 

 crops by the aid of the light, and although we have succeeded 

 with several species, we have now given up for the time being all 

 commercial or so-called practical considerations, and we are now 

 endeavoring to discover the fundamental facts concerning the 

 exact composition of the arc light, and its direct action upon 

 vegetable tissue and physiological processes. Although this may 

 seem to be driving the cart before the horse, it is nevertheless the 

 necessary and logical order of experiment in untravelled fields, 

 because we have first to discover the phenomena before we can 

 search for their causes. 



Our first experiment was with a naked two thousand candle- 

 power lamp hung inside a forcing-house and running all night. A 

 forcing-house sixty feet long and twenty feet wide was divided by 

 a partition, one part being run in the ordinary manner, the other 

 receiving electric light at night in addition to the normal daylight. 

 The general effect of the light was to greatly hasten maturity, and 

 the nearer the plants grew to the light the greater was the acceler- 

 ation. This tendency was particularly marked in the leaf-plants, 

 endive, spinach, cress, and lettuce. The plants "ran to seed" 

 before edible leaves were formed, and near the light the leaves 

 were small and curled. This is well illustrated in spinach. The 

 electric light spinach matured and produced good seeds while that 

 in the dark house was still making large and edible leaves, with no 

 indication of running to seed. An examination of leaves of the 

 plants under the microscope showed that while there was appar- 

 ently the same amount of starch in each, it was much more 

 developed in the electric light specimen, the grains being larger 

 and having more distinct markings, and giving a better color test 

 when treated with iodine. Lettuce, growing in a row nearly 

 under the lamp, behaved in a similar manner. F<n' three feet 

 either side of the lamp, most of the i)lants were killed outright 

 soon after they came up, and the remaining ones in the entire row 

 (tlnrty-five plants) wei'e seriously injured, the leaves curling and 

 remaining very small. The plants increased in stature, vigor, 



