. The art of projecting. A manual of experimentation in physics, chemistry, and natural history, with the porte lumière and magic lantern. ure. But it is with the vertical attachment that the mostnovel and interesting phenomena, due to cohesion, maybe shown. For this purpose it is necessary to have ahorizontal tank, made by cementing a ring, an inchbroad and four or five inches in diameter, upon a plateof clear glass. The ring may be made of glass, orwood, or zinc. This is to be placed upon the hori-zontal condenser, and half filled with pure water, the 48 THE ART OF PROJECTING. surface of whi
. The art of projecting. A manual of experimentation in physics, chemistry, and natural history, with the porte lumière and magic lantern. ure. But it is with the vertical attachment that the mostnovel and interesting phenomena, due to cohesion, maybe shown. For this purpose it is necessary to have ahorizontal tank, made by cementing a ring, an inchbroad and four or five inches in diameter, upon a plateof clear glass. The ring may be made of glass, orwood, or zinc. This is to be placed upon the hori-zontal condenser, and half filled with pure water, the 48 THE ART OF PROJECTING. surface of which is to be projected. Let fall, from aheight of two or three inches, a single drop of assumes a characteristic form, will move about, butwill last only a few seconds, as it evaporates out the tank, and fill again with pure water, andin like manner drop upon its surface any of the essen-tial oils, of creosote, lavender, turpentine, sperm, andcolza oils. Each one will assume its peculiar form dueto cohesion. Fig. 29 represents the pattern exhibited by a singledrop of oil of coriander, and Fig. 30 the appearance. Tig. 29. Tia- 30. of oil of cinnamon. Some of these forms are verybeautiful, as, for instance, that due to oil of method of studying oils is used, by some experts,to determine their kind and purity. These forms areknown as Tomlinsons Cohesion Figures. Again, into the same tank, well cleaned and filled withwater, drop a few small pieces of camphor-gum. Assoon as they touch the water they will begin to moverapidly, dodging each other in a wonderful way, and ap-pearing as if they were endowed with life. Their move-ments will be accelerated if the water is warmed to ahundred degrees, or a little more. PHYSICAL EXPERIMENTS. 49 A drop of a solution of camphor in sulphuric acid,gently delivered to the surface of the water, will take adouble-convex lens shape, and will move about thewater in an eccentric manner for a long time. Severaldrops
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Keywords: ., bookcentury1800, bookdecade1870, bookpublisherbosto, bookyear1877
