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Casein
July, 1914.]
CURRENT TOPICS.
I25
Casein. ANON. (SCi. Amer., cx, No. II, 227.)--Consul W. H. Hunt, of St. Etienne, France, forwards an interesting report on some recent notable developments in the production and industrial uses of casein. Casein, the principal albuminoid matter of milk, is now obtained by electrolysis, according to the following recently invented process: In the middle of a large vat of skimmed milk, heated to 8o ° C., there is placed a porous vessel containing a 5 per cent. solution of sodium hydroxide; an iron cathode is plunged in the soda and a carbon anode in the milk. An electric current set~ free the phosphoric acid contained in the milk, and the casein precipitates. As compared with the method of obtaining casein by the use of acids or rennet, the cost of this process is very low, the yield is greater, and the casein produced contains no foreign ingredients. Vegetable casein, now produced on a large scale from the soya bean, can be put to the same uses as animal casein. The principal use of casein is in the manufacture of galalith (milk-stone), used as a substitute for ivory, tortoise-shell, celluloid, etc. Penholders, frames, purses, phonograph discs, and a great variety of other articles are nOW made of galalith. It is also used as a chemical fertilizer. Several other casein products have recently been introduced. M e r c u r y - V a p o r L a m p . BILLON-DAGUERRE. ( La Revue Elec., Dec. 19, I 9 1 3 . ) - - A note on a water-cooled, mercury-vapor quartztube lamp with projecting mirrors. The lamp consumes 18 amp&res at 70 volts, or about 126o watts, and gives about 3000 candle-power. The principal feature of the lamp is that it produces practically " c o l d " light. For example, this light may fall for any length of time on celluloid, etc., without producing a heating effect on or deformation of the illuminated portion. This feature is especially advantageous for microscopy and for photography. P r e s e r v a t i o n of W o o d . A. J. WALLIS-TAYLER. (J. Roy. Soc. Arts, Ixii, 2 8 6 . ) - - W o o d should be seasoned for at least 6 to 12 months before treatment. ( I ) Kyanizing consists in steeping timber in a I per cent. solution of mercury chloride for 7 to II days.
(2)
Burnettiging comprises preliminary steaming, followed by impregnation in a 2 ~ to 2 per cent. solution of zinc chloride under a pressure of 7 to 8 atmospheres. In the ginc-tannin or Wellhouse process, treatment in a partial vacuum follows the preliminary steaming, a small percentage of glue is added to" the zinc chloride, and after impregnation for 21~ to 6 hours at IOO to 125 pounds pressure per square inch, the timber receives a final treatment with a 0. 5 per cent. solution of tannin under the same pressure for two hours. (3) Creosoting usually involves steaming of the dried timber, heating under reduced pressure, and treatment with creosote oil under a pressure of IOO to 18o pounds per square inch. The amount of creosote absorbed by the timber varies from 7 to 2o pounds per
CURRENT TOPICS.
I25
Casein. ANON. (SCi. Amer., cx, No. II, 227.)--Consul W. H. Hunt, of St. Etienne, France, forwards an interesting report on some recent notable developments in the production and industrial uses of casein. Casein, the principal albuminoid matter of milk, is now obtained by electrolysis, according to the following recently invented process: In the middle of a large vat of skimmed milk, heated to 8o ° C., there is placed a porous vessel containing a 5 per cent. solution of sodium hydroxide; an iron cathode is plunged in the soda and a carbon anode in the milk. An electric current set~ free the phosphoric acid contained in the milk, and the casein precipitates. As compared with the method of obtaining casein by the use of acids or rennet, the cost of this process is very low, the yield is greater, and the casein produced contains no foreign ingredients. Vegetable casein, now produced on a large scale from the soya bean, can be put to the same uses as animal casein. The principal use of casein is in the manufacture of galalith (milk-stone), used as a substitute for ivory, tortoise-shell, celluloid, etc. Penholders, frames, purses, phonograph discs, and a great variety of other articles are nOW made of galalith. It is also used as a chemical fertilizer. Several other casein products have recently been introduced. M e r c u r y - V a p o r L a m p . BILLON-DAGUERRE. ( La Revue Elec., Dec. 19, I 9 1 3 . ) - - A note on a water-cooled, mercury-vapor quartztube lamp with projecting mirrors. The lamp consumes 18 amp&res at 70 volts, or about 126o watts, and gives about 3000 candle-power. The principal feature of the lamp is that it produces practically " c o l d " light. For example, this light may fall for any length of time on celluloid, etc., without producing a heating effect on or deformation of the illuminated portion. This feature is especially advantageous for microscopy and for photography. P r e s e r v a t i o n of W o o d . A. J. WALLIS-TAYLER. (J. Roy. Soc. Arts, Ixii, 2 8 6 . ) - - W o o d should be seasoned for at least 6 to 12 months before treatment. ( I ) Kyanizing consists in steeping timber in a I per cent. solution of mercury chloride for 7 to II days.
(2)
Burnettiging comprises preliminary steaming, followed by impregnation in a 2 ~ to 2 per cent. solution of zinc chloride under a pressure of 7 to 8 atmospheres. In the ginc-tannin or Wellhouse process, treatment in a partial vacuum follows the preliminary steaming, a small percentage of glue is added to" the zinc chloride, and after impregnation for 21~ to 6 hours at IOO to 125 pounds pressure per square inch, the timber receives a final treatment with a 0. 5 per cent. solution of tannin under the same pressure for two hours. (3) Creosoting usually involves steaming of the dried timber, heating under reduced pressure, and treatment with creosote oil under a pressure of IOO to 18o pounds per square inch. The amount of creosote absorbed by the timber varies from 7 to 2o pounds per