GARDENING AS A SCIENCE. 
II 
opinion ; especially as the recent discoveries have shown in what tremendous 
volume electricity is combined with the elements of matter. 
If, then, solar power operate such grand phenomena, should we err in an 
endeavour to trace to the same causes all the developments of vegetable structure \ 
Some have positively asserted that certain plants coruscate, or emit flashes of 
light. Not having witnessed any of the circumstances which are recorded in 
Dr. Darwin's Botanic Garden, their accuracy cannot be vouched ; but it would 
be interesting to investigate the following statement, given on the authority of a 
Mr. J. R. Trimmer, who refers the flashings to electricity. He says : — " In 
Walking in my garden in the evening, in which was a considerable quantity of the 
Nasturtium, in bloom, not at all thinking of the flashing of plants, I was struck 
by the very vivid flashes that proceeded from them : the scintillations were the 
most brilliant that I had ever observed, and at the same time the sky was overcast 
with a thunder-cloud ; directed by this circumstance, I have, on several occasions, 
looked for the flashes when in the evening there have appeared electric clouds 
collecting, and have always found them at that time most to abound and to be 
most brilliant." 
There is nothing to startle in these assertions ; for though few may have 
observed flashes of fire, none can doubt the powerful attractive influence of solar 
light ; witness the expansion of the flowers of all the Mesembryanthemums under 
the direct ray, and the surprising movements of the leaves of most Fapilionacece. 
The foliage of growing Erythrinas, when quiescent, is nearly level in position ; 
but no sooner does it feel the power of the sun than its leaflets begin to rise, till at 
length, during the blaze of day, they become almost perpendicular, and appear as 
if they struggled to rush aloft. Gradually, as the day declines, they relax, and at 
midnight assume an exactly opposite direction, pointing to the earth : these changes 
exist no longer when the plant, though clothed with leaves, has ceased to grow. 
All nature is replete with light : the two gases, oxygen and hydrogen, are 
perfectly invisible ; but when mixed and ignited, they explode violently with a 
great flash of light, or consume slowly in a stream of fire, according to the 
precautions employed, producing an intensity of light and heat, which surpasses 
ordinary conception. Every act of friction or percussion yields evidence of concealed 
fire, and so does each familiar instance of combustion. 
The opposite of light, or its modification, which we call shade, is worthy of 
much study. By shading, or by placing plants impatient of sun in a north aspect, 
the gardener preserves in blooming health his camellias, azaleas, and Ericaceae. 
Shade, by means of a semi-transparent screen, promotes the diffusion and softening 
of the ray, and thus wards off much danger of scalding, without weakening its 
influence. But as the beams are the agents of colour, especially during the 
maturation of fruit, it is philosophical to presume, that, coincident with the 
admission of much air, their utmost power is essentially required to perfect the last 
important process of vegetable existence. 
