THE 
HORTICULTURAL REGISTER, 
October 1st, 1834. 
HORTICULTURE. 
ARTICLE I.—ON CHEMISTRY, 
AS CONNECTED WITH THE DEVELOPEMENT AND GROWTH OF PLANTS. 
By the Author of the Domestic Gardeners' Manual. 
FIFTH ARTICLE. 
Light.—I am now arrived at the point, from which my theory starts: 
the fulcrum upon which it rests, and by which it is supported. 
It is usual to consider light as connected with colour; in other 
words, to view it prismatically; and so viewed, its operation and 
agency are most mysterious. I leave these considerations, how¬ 
ever, to a Newton, or a Goethe : it is to the vegetable, vital princi¬ 
ple that I direct my chief attention, in as much as it is the agency 
of light upon plants, and their sources of nutriment, in which the 
gardener is most deeply interested. 
Lavoisier, writing upon the developement of light, observes (Elem. 
Vol. 1. p. 54.) “In the present state of our knowledge, we are unable 
to determine whether light be a modification of caloric," (heat) or if 
caloric be, on the contrary, a modification of light. This, however, 
is indisputable, that in a system where only decisive facts are admis¬ 
sible, and where we avoid, as far as possible, to suppose anything to 
he that is not really known to exist, we ought provisionally to distin¬ 
guish, by distinct terms, such things as are known to produce dif¬ 
ferent effects. We, therefore, distinguish light from caloric ; though 
we do not, therefore, deny that these have certain qualities in com¬ 
mon, &c. &c.” 
The father of modern chemistry herein, as in most other of his 
luminous and truly candid statements, made a great advance; but in 
his day electricity had excited little attention, and was comparatively 
little known or studied. Perhaps the scientific world is more deeply 
indebted to the illustrious Davy than to any other individual philo- 
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