CEMENTS.
Grove’s Mastic and Bismuth.—Dissolve gum mastic in chloroform, and thicken with nitrate of bismuth. The solution of mastic should be nearly saturated.
Grove’s Oxide of Zinc, Dammar, and Drying Oil.—Rub up well-ground oxide of zinc, 2 ozs., with drying oil, to the consistence of thick paint. Then add an equal quantity of gum dammar, previously dissolved in benzoline, and of the thickness of syrup. Strain through close-meshed muslin. Keep in well-corked bottle, and, if necessary, thin with benzoline.
Isinglass Cement.—Heat the isinglass in a covered vessel on the water-bath with a little glacial acetic acid, until it is thoroughly softened and forms a stiff mass, then gradually add more acid until it produces a thick solution which is of uniform consistence, and just fluid while hot. Then run into wide-mouth bottles and close with good corks.
Kitton’s Cement of white lead and red lead in powder, and litharge powder in equal parts. Grind together with a little turpentine, until thoroughly incorporated, and mix with gold size. The mixture should be thin enough to use with a brush; in using, one coat should be allowed to dry before applying another. No more cement should be mixed with the gold size than is required for immediate use, as it sets quickly, and becomes unworkable.
Krönig’s Cement.—Gradually add ordinary resin, 7 to 9 parts, to melted beeswax, 2 parts, then steam and cool.
Shellac Cement.—Dissolve shellac in an equal weight of methylated spirit, then pour off the clear portion and add a few drops of balsam and castor oil.
Marine Glue.—Dissolve indiarubber in mineral naphtha, and add twice the quantity of powdered shellac; or make chloroform the solvent, and use mastic instead of shellac. For casting battery trays, use a composition of 4 parts resin and 1 of gutta percha, with a little boiled oil.
Selier (Cleaning Glass Slides).—New slides or cover-glasses must be placed for a few hours in a mixture of 1 part of potassium bichromate, 1 of sulphuric acid, and 25 of water. Subsequently wash with water and wipe dry with a linen rag, after draining off the excess of moisture. Covers that have been used should be previously immersed for a few days in a mixture of equal parts of alcohol and hydrochloric acid. Scrape old slides free of mounting medium before immersing them in the bichromate solution.
Elsching’s Celloidin Solution.—Allow the celloidin shavings to swell up for 24 hours in the necessary quantity of absolute alcohol, then add the proper amount of ether.