. The art of projecting. A manual of experimentation in physics, chemistry, and natural history, with the porte lumière and magic lantern. t long enough,each of the prismatic tints will appear in turn upon thewalls, and sometimes the series will be repeated. If the bubble is projected in the way mentionedupon page 44, three or four of these series may be seenat the same time. Instead of blowing a bubble with a pipe, as shownin that figure, blow a mass of them in the dish con-taining the solution. Very large masses may be madeand the colors reflected from them in the same way asabove, or with t
. The art of projecting. A manual of experimentation in physics, chemistry, and natural history, with the porte lumière and magic lantern. t long enough,each of the prismatic tints will appear in turn upon thewalls, and sometimes the series will be repeated. If the bubble is projected in the way mentionedupon page 44, three or four of these series may be seenat the same time. Instead of blowing a bubble with a pipe, as shownin that figure, blow a mass of them in the dish con-taining the solution. Very large masses may be madeand the colors reflected from them in the same way asabove, or with the lantern. The tension of the bubble film may be shown byleaving the tube open after the bubble is blown, whenthe latter will contract as if it were being drawn intothe bowl of the pipe ; or the bubble may be blown uponthe end of a glass tubebent twice at right an-gles, after which theopen end may be putan inch or two underthe surface of water inthe chemical tank and Fig, 8r>. projected. The water in the tube will stand below thelevel of the water in the tank indicating pressure. When these colors from thin films appear upon the. lo8 THE ART OF PROJECTING. screen, pieces of glass of various colors may be inter-posed between the lens and the bubbles, when dark orblack bands will be seen to take the place of thosecolors that have been stopped by the tinted glass. Yellow light that is nearly monochromatic can beobtained by interposing a crystal of bichromate ofpotash. Let the crystal be a thin and quite clear one. Colored solutions may be used for the same purpose. Under the head of Spectrum Analysis other meansfor producing monochromatic light will be found, withcolored lights which are appropriate for examiningbubbles. Bubbles made of common soap-suds will not lastlong, and various preparations have been describedfor making persistent bubbles, some of which wouldlast three days. A piece of glycerine soap about the size of a marble,sliced and dissolved in water at a iio° Fa
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Keywords: ., bookcentury1800, bookdecade1870, bookpublisherbosto, bookyear1877
