Fifty-five elements are presented to us by nature: of these, only four are employed in the elaboration of all the wonderful creations of living matter."

"Flowers and perfumes, leaves and wood, food and poisons,-flesh, fat, hair, feathers,-when the chemist comes to look at all these, he finds that such wonderful diversity is the result, not of the employment of a multiplicity of elements, but of the combination of a very few, in varied proportions, and under the influence of vital agency."

To render this extraordinary fact still more impressive, a tabular statement is here subjoined of the analysis of ten proximate principles, Gum, Sugar, Starch, Lignin or woody fibre, Wax and Gluten are of vegetable origin; Gelatin, Albumen, Fibrin, and Fat, are of animal origin.

From this statement, we discover that the proximate principles of Vegetables, with the exception of Gluten, contain but Three elements, and that those of Animals, with the exception of Fat, contain Four; and whilst its composition is closely analogous to that of most vegetable principles, that of gluten approximates to the composition of most animal principles. The important consequences of these discoveries will become apparent at a future stage of our inquiry.

All ponderable elements, and the host of natural and artificial compounds in which they exist, are subject to the imponderable agencies of Light, Heat, and Electricity, which modify and control all chemical changes, but more particularly those of organic productions.

The chemist is totally ignorant of the ultimate nature of these imponderable or ethereal matters; he cannot experiment with them as with solids, liquids, gases, or vapours; he is only acquainted with them when acting upon such ponderable forms.

Solar light enters the confines of the atmosphere, permeates its transparent volume with incredible velocity, and illuminates the solid opaque earth.

Such light is absolutely necessary for the welfare of the animal and vegetable creation; its presence stimulates a healthy action of their vital functions, and causes the elaboration of elements that enter into the constitution of organized structures; whilst, in the prolonged absence of light, morbid and fatal changes will generally ensue.

The power and goodness of God are magnificently displayed in solar light, it being, not of one colour, but of seven colours, a fact that we behold with admiration and gratitude, in the stupendous arch of varied light, which so frequently spans the heavens as the rainbow.

"Look upon the rainbow, and praise Him that made it, very beautiful it is in the brightness thereof; it compasseth the heavens about with a glorious circle, and the hands of the Most High have bended it." The very limited extent to which scientific inquirers can reason and experiment upon an element so inconceivably attenuated as solar light, leads them to consider that the bow may be caused by the coloured refraction of light by drops of rain, for it is found that when the solar rays are caused to impinge upon watery spray, similar colours to those of the rainbow appear, although microscopic in comparison with its gigantic span.

These colours likewise appear when the solar beam is refracted by the denser solid medium of flint glass, a triangular prism of this invaluable compound, probably elicits the phenomenon in the greatest perfection and beauty attainable by human skill; hence the term Prismatic colours applied to the Red, Orange, Yellow, Green, Blue, Indigo, and Violet rays of light which constitute the spectrum.

When these Seven coloured rays are collected to a focus, by a glass lens, they coalesce into colourless

light, and are therefore presumed to constitute such ethereal agent.

The chemist discovers that the coloured rays are possessed of different chemical powers; that the red have the highest, and the violet the lowest temperature; that the former have but little, and, in some instances, no tendency to promote chemical changes, whilst the latter are most powerful excitants of such phenomena.

If solar light were of one colour, or mono-chromatic, all terrestrial objects would appear of such colour, or, if incapable of reflecting it, they would appear black, we should not be charmed with the varied and gorgeous hues of the creation; but light being sevencoloured, or chromatic, and the surfaces of objects being differently constituted, both physically and chemically, they are capable of reflecting, in some cases, all the rays, and thus of appearing white; and, in other cases, of absorbing them all, and thus of appearing black; but more generally of reflecting certain simple rays, or mixtures of rays, in preference to others, and of thus impressing the eye with numerous shades of colour.

Light, is accompanied by heat during its swift passage from the sun to the earth, but heat is an imponderable element, and therefore the chemist is obliged to rest content with examining its effects upon terrestrial objects; and although he can artificially elicit heat by various experiments, he is even then ignorant of its nature.

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"In all our excursions over the surface of the globe, innumerable objects excite our admiration, and contribute to inspire delight; but whether our gratitude is awakened by the verdure of the earth, the lustre of the waters, or the freshness of the air, it is to the beneficial agency of heat, under Providence, that we are indebted for them all.

"Without the presence and effects of heat, the earth would be an impenetrable rock, incapable of supporting animal or vegetable life; the waters would be for ever deprived of their fluidity and motion; and the air of its elasticity and utility together.

"Heat animates, invigorates, and beautifies all nature; its influence is absolutely necessary to enable plants to grow, put forth their flowers, and perfect their fruit;—it is closely connected with the powers of life, since animated beings lose their vitality when heat is withdrawn.

"Such is the universal influence of this powerful agent in the kingdoms of nature; nor is this influence diminished in the provinces of art; it is with the aid of heat that rocks are rent, and the hidden treasures of the earth obtained; matter is modified in countless ways by its agency, and rendered subservient to the uses of man; furnishing him with useful and appropriate implements, warm and ornamental clothing, wholesome and delicious food, needful and effectual shelter."

Solar heat, and artificial heat, are indeed powerful agents; the former most particularly, as con

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