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This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1816 Excerpt: ...that a black line can be formed, either by brown and purple, by blue, red and yellow, or by green and red. The following expert ment makes the analogy still stronger. Having made a very weak solution of soap and water, and having immersed the egg-cup, I held the film at right angles to the horizon, and perceived a number of perfectly black lines to form at the top; as they descended they dilated, and as they dilated they became differently coloured as already described. Here the analogy between the two experiments becomes nearly perfect, with this slight difference, that each coloured series could not be again condensed into a black line, as in the third experiment. Thus we might infer, that a soap film is compounded of aqueous and saponaceous atoms, which when placed at regular distances, according to the laws of repulsion and attraction, appear all over of a gray and semi-transparent colour. On the other hand, when in consequence of the subsidence of the fluid parts or from any other cause, the uniformity of condensation is destroyed, these atoms are condensed into different lines: thus, a line of atoms in a state of white condensation, reflects a white colour: a line of atoms in a state of blue condensation, a blue colour, and so of the rest. The next experiment brings us better acquainted with those atoms. EXPERIMENT 14th. VARIEGATED LINES ARE CURVED INTO CONCENTRIC RINGS, AND SCATTERED BY AGITATION INTO A CONFUSION OF ATOMS, Haying dipped the egg-cup into the saponaceous solution; when covered with the watch glass, I held it perpendicular to the horizon, until the variegated lines were formed, and a silvery arch occupied the top. I gently turned the cup, so as to bring the film to a horizontal position, and placed it on the window-stool, resting on the...