great.

Further experiments were made by excluding the sun during the day and
exposing the plants to the diffused electric light only. In all cases,
with radishes, lettuce, peas, corn, and potatoes, the plants died in
about four weeks. Only a little starch and no chlorophyl was found in
the plants deprived of sunlight and only receiving the electric light.
Thus the experiments with a naked light showed conclusively that
"within range of an ordinary forcing house the naked arc light running
continuously through the night is injurious to some plants." In no
case did it prove profitable.

Experiments with the light inclosed in a white globe and running all
night were different in their results. The effect was much less
marked. Lettuce was decidedly better in the light house; radishes were
thrifty but did not produce as much as in the dark house. A third
series of experiments with the naked light running a part of the night
only were also made. Radishes, peas, lettuce, and many flowers were
experimented upon. The lettuce was greatly benefited by the light.
"Three weeks after transplanting (Feb. 5)," we are told, "both
varieties in the lighthouse were fully 50 per cent. in advance of
those in the dark house in size, and the color and other characters of
the plants were fully as good. The plants had received at this time
70½ 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 161¾ hours of electric light, worth at current prices of
street lighting about $7."