. The botanist's companion; or, Directions for the use of the microscope. Botany; Microscopy. PRESERVATION OF OBJECTS. 29 of water). A thin slip of glass, sufficient to cover the object and paper- slips, is put on; the slips are gummed, and the thin glass applied to its place, where it is retained by the gum drying. The whole may be secured by pasting a long slip of paper over all, with a hole for the object. The advantage of this method is preventing running in. Chloride of calcium being deliquescent, never dries up, and, if evaporation takes place, water is easily introduced at the open side
. The botanist's companion; or, Directions for the use of the microscope. Botany; Microscopy. PRESERVATION OF OBJECTS. 29 of water). A thin slip of glass, sufficient to cover the object and paper- slips, is put on; the slips are gummed, and the thin glass applied to its place, where it is retained by the gum drying. The whole may be secured by pasting a long slip of paper over all, with a hole for the object. The advantage of this method is preventing running in. Chloride of calcium being deliquescent, never dries up, and, if evaporation takes place, water is easily introduced at the open sides of the thin glass. The points to be attended to are—1, that the paper between the glasses be thick enough to prevent much pressure on the object, and not so thick as to allow it to float about or fall out at the side; 2, that the drop of solution be not too large, but covering the object, and yet not reaching the paper. Glycerine may be used in place of chloride of calcium in cases where the objects are very delicate, or contain chlorophyll or albumen. Small specimens for the microscope, such as Diatoms and Desmidieae, and many small Sea-weeds, as well as vegetable tissues, are put up in slides 3 inches long by 1 broad (fig. 17), in the centre of which there is a circular cavity formed by a layer of asphalte,* and covered by a circular piece of thin glass. The asphalte is applied by means of a hair pencil, the slide being placed on a moveable brass disc (fig. 18), which has circular marks on it corresponding to the required dimensions of the cavity. The depth of tlie cavity can be varied accord- ing to circumstances, by putting one or more layers of asphalte. After the thin glass cover is put on, it is luted carefully with asphalte. The cavity is filled with distilled I'ig- i"- water, weak pyroligneous acid, alcohol, diluted glycerine, a very weak solution of creazote (one drop to the ounce of distilled water), or some other fluid. "When specimens are very minute,
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Keywords: ., bookcentury1800, bookde, booksubjectbotany, booksubjectmicroscopy
