This section is from the book "The Gardener's Monthly And Horticulturist V22", by Thomas Meehan. See also: Four-Season Harvest: Organic Vegetables from Your Home Garden All Year Long.
(Concluded from page 120).
Thus prepared, the six glasses were placed side by side, in the light, in the temperate house of the Museum. These experiments, to all appearance so simple, proved a veritable labor of Hercules, and without the assistance of the skillful and intelligent superintendent of the temperate house, M. Newman, I should most assuredly have been unable single-handed to carry out the experiment without changing the conditions, as during the extremely hot weather it was necessary to water the young plants twice a day to keep them alive. Nor was this all. It was necessary during the course of the experiment to change the fluids colored with aniline every four or five days, according to the intensity of the sunlight. The other colored fluids were more permanent, and required changing less often.
After carrying on these experiments most carefully all through the summer, the following results were obtained: The plant exposed to the violet light exhibited a luxuriant growth, its foliage was of a fine deep green, and very abundant as compared with that of the five others. That was all. The plant had neither blossomed nor fruited, clandestinely or otherwise.
The plant exposed to blue light had made an ordinary growth - nothing exceptional. That, too, was all. No fructification.
The plant exposed to the green rays had grown badly. It was ailing and nearly dead, notwithstanding the intervention of the white light. The disastrous effects of green light on plant life had not been mitigated by the white light from above. This perfectly accords with M. Bert's observations.
The plant exposed to yellow light had made an average growth - rather under than over; but it had flowered and fruited as well, and very rapidly. The fertilization was clandestine still.
The plant exposed to orange light had grown rather badly, and looked ailing.
The plant exposed to the red light had grown nearly, perhaps not quite as well as that exposed to violet light.
None of these plants, with the exception of that exposed to yellow light, had fruited or even flowered.
Now, why this exceptional developement?
A thermometer placed in the glass furnished the explanation. The temperature in the glass exposed to the yellow light was much more elevated than that of any of the other glasses, contrary to all theory, as the red and orange rays being the least refractory should have given the highest temperature. I leave physicists to explain the phenomenon.
I pointed out the rapid growth of the plant exposed to the yellow light to M. Houleau, who was much surprised at it, and remarked that whenever before he had exposed plants to the action of yellow light, they had been killed off as quickly and surely as though they had been put in the fire. But I called his attention to the fact that here there had been an interposition of white light, which appeared to have mitigated the effects in a very remarkable manner. In other respects, M. Houleau's experience accorded with what might have been anticipated from the great increase of temperature in the yellow light.
These experiments were repeated during three consecutive years, and always gave the same identical results. In six other glasses, similarly disposed, we planted six seeds of the same plant, but the disheartening tardiness of their vegetation hindered any observations.
It will be seen that our special object was not attained. The stimulus which was to raise this singular plant out of its abnormal frame of existence produced no effect upon it whatever. Its clandestine mode of fertilization was steadily repeated - that is, whenever fertilization occurred. But if we failed in our purpose, the conclusions deducible from our experiments are none the less interesting and calculated to prove useful in a horticultural point of view.
Despite their very restricted scope, limited as they were to a solitary little plant, our observations established the persistent recurrence of certain phenomena justifying the following conclusions: 1. That plants exposed to violet light, modified by white light, grow luxuriantly, thus partially confirming the experience of General Pleasanton.
2. That plants exposed to yellow light, always supposing it to be mitigated by white light, fruit very rapidly. These facts, we repeat, are likely to prove of great utility in horticulture.
We purposed repeating the experiments above described, so as to ascertain whether the same results are obtained when plants are grown in glass houses provided with violet, yellow, and white lights.
These experiments promised to be of great utility, but unforseen circumstances have obliged us to postpone them for the present. We hope to resume them at some future day.