560 CURRENT TOHCS.

Zinc Alloys Heated in Vacuo. T. TURNER," (Inst. o/ Metals, Jan., I912 . ) - - I t is found that zinc and other metals, are entirely removed from brass and other copper-zinc alloys when they are heated" in a vacuum. In the case of brass the separation of the zinc is quantitative, provided the temperature does not exceed I2oo ° C. and the heating is not too prolonged: by subjecting a sample of " poisoned" brass to this treatment all the zinc. lead, and arsenic and a little of the tin were removed at I2oo ° C. Zinc volatilizes easily at 375 ° C. in a vacuum, and is readily volatilized from 6o/40 and 70/3 ° brass at temperatures of 520 ° C. and 540 ° C. respectively. When I8o grammes of 7o/3 ° brass were melted in a crucible and allowed to cool in an exhausted desiccator, the per- centage of zinc in the alloy was sensibly reduced, although the charge could not have remained liquid for more than 3 minutes. On heating zinc with copper in z,acuo, though the metals were not in contact, the copper rapidly turned yellow at 38o ° C., the zinc being still solid. When hard zinc (tt{e residue from galvanizing baths, containing about 5 per cent. of iron ) was heated to 5oo ° C. in a vacuum, the zinc was completely volatilized, the iron remaining in the residue. T h e application of this principle to the refining of crude copper, brass scrap, hard zinc. etc., is suggested.

Ice Drif t in Polar Regions. O . A . AKESSOX. (Ark. [iir Mat. Astrou. och. Fysik. Stockholm, vi, No. 40, I . ) - - I n polar regions the methgd generally employed for determining latitude and longitude involves the observation of two altitudes of the sun or other celestial object and the corresponding times. This supposes the observer fixed. If the observer be on a moving ice-field, it is possible so to arrange the observations that the position and velocity and direction of the observer may be calculated. Four observations nmst be taken of the altitude of the celestial object, and the corresponding times. If the time between the first and second observations and between the third and fourth be six hours, while that between the second and third be several days, the positions are determinable, and from these the velocity and direction of the motion of the ice is easy to compute.

Chicle Gum. J . E . Q . Bosz and N. H. COHEN. (Arch. Pharm., ecl, 52 . ) - -The larger portion of chicle gum, which is obtained in Mexico and Central America from Achrcts sapota, goes to the United States, where it is manufactured into chewing gum. The authors have examined it, as Schereschewski did, and find that a-chiclalban consists of almost pure a-amyrin acetate, B-ehiclalban is a mixture of lupeol and a- and fl-amyrin combined with caproic. acetic, and cinnamic acids. It appeais probable that r-chiclalban is identical with cerotinone. Chielafluavil is a mixture of all the con- stituents of the chicle gum.