Gleanings from Foreign Journals.
By J. ROBERT MOECHEL.
Thorough Extraction of Vegetables.—A considerable quantity of water and sometimes application of heat is necessary for completely extracting tannin and coloring matters from plants. Dr. O. Kohlrausch, of Vienna, claims that a small amount of water is needed, and that very concentrated solutions are obtained at a low temperature, by operating as follows:
The material to be extracted is covered with water, and macerated for some time at a pressure of one atmosphere. The water penetrates the cellular tissue, dissolves the coloring matter, and, by way of diffusion, the water becomes saturated to the same degree as the liquid in the cells. Separating the liquid, and repeating the operation several times, under the same conditions, secures the complete extraction of coloring Matter—Erfindungen und Erfahrungen, Wien, i, 1885.
Syrup of Pineapple.—Cut 5 kilos of selected pineapples in small pieces, transfer into a bottle, add 5 kilos each of white wine and water, and macerate at a medium temperature for several days. Boil 30 kilos of sugar with 20 kilos of water, add the strained infusion, heat to ebullition, and strain through flannel.
Syrup of Apricot.—Digest, for six days, 5 kilos each of white wine, water and ripe apricots, freed from stones and cut into small pieces; strain, press very gently, and add to the hot syrup, prepared as above of 40 kilos of sugar and 30 kilos of water. When cold, add 200 Gm. of artificial essence of apricots.—Erfind. und Erfah.
Shoe Blacking.—Mix 100 parts bone black, 50 parts glycerin, 5 parts oil and 10 parts of vinegar. This blacking is said to give excellent shine, and to keep the leather smooth and soft.
Transparent Glue for Porcelain.—Dissolve 75 Gm. caoutchouc, in small pieces, in 60 Gm. of chloroform; add 15 Gm. of mastic, and dissolve without heat.—Chemiker Ztg., No. 14, 1885, p. 254; Nature, 1884, xii, p. 587.