Читать книгу The Pyrotechnist's Treasury; Or, Complete Art of Making Fireworks - Thomas Kentish - Страница 13

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Take half an ounce of dextrine, and 5 ounces, or a quarter of a pint of cold water, put the dextrine into a cup or basin, add a little of the water, and mix it well with a teaspoon, rubbing it till all is dissolved; then add the remainder of the water, stir well together a second time, pour it into a vial, and cork for use. Dextrine, wetted to the consistency of honey, may be used instead of thick gum-arabic water, for pasting. For this purpose it is advisable to keep either in a wide-mouthed bottle, and to set the bottle in a gallipot containing a little water; the brush, a camel's-hair pencil, or very small sash-tool with ¹⁄₃ of the bristles cut away on each side, to render it flat, can then be kept in the water, when not in use; this will prevent it, on the one hand, from becoming dry and hard; and, on the other, from getting clogged and swollen. It can be squeezed between the thumb and fingers, when wanted for use. The flat gum brushes now sold, bound with tin, are not pleasant to use, as the tin oxidises, and turns of a disagreeable brown colour. If there is a difficulty in obtaining a graduated water measure, one sufficiently correct for pyrotechnic purposes may be made with a vial. Paste a narrow strip of paper up the outside of the vial, weigh 4 ounces of water in a cup, in the scales: pour it into the vial, mark the height, and divide it into 4 equal parts, for ounces; of course, it can be graduated into half and quarter ounces, and increased, if large enough, to 5 or more ounces. A gallon of distilled water weighs exactly 10 pounds. Consequently, a pint of pure water weighs a pound and a quarter. This is also near enough for spirit, though, of course, spirit is a trifle lighter. Doctors' vials are often marked with ounce divisions.