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\=3 G_r tr-j -S', References to Recent Literature - B 33 THE COMPARATIVE RESISTANCE TO VENTILATION OF MINE ROADWAYS, INCLUDING THE WORKING FACE. R. Clive. Trans. Instr.. Min. Engrs. (London) 95, 325-33 (July 1938), (British). The coefficient of friction for a straight and uniform arched-girder, roadway, lined with brickwork to the springline of the arch, i3 low and approaches that for a smooth-lined airway. A slight variation from the straight appreciably in creases resistance, as does variation in crosc-suctional area. The resistance caused by tubs (ir cars) is considerable and nay increase the coefficient for a particular roadway by as much aB 100 per cent. The resistance along the working face is very high compared with that for a normal rordway. 34 SOME NOTES ON NATURAL VENTILATION. B.K. Lawton, J. Chec;, Metal. Min. Sac. Sc. Africo 34, 61--1 (August 1938). Some interesting observations were nodo on the seasonal variation of natural ven tilation in a cine about 2,200 ft. Jeep at the pit bottoms and approximately 3,300 ft. doep at tho workings. Airflow by gravity varied from a maxinun of 150,000 c.f.c, in February, when the surface air tomperature was 31F, to a minimum of 7?,000 c.f.c. in August with a surface temperature of 57. This in herent variability of airflow, and tho difficulty in ventilating new dovelopnent ends are hold to bo a drawback to genoral adoption of natural ventilation. Never theless, ovary effort should be made in planning out workings eo as to take full advantage of the gravity effect. . IKS DETERMINATION OF THE SPECIFIC SURFACE OF POWDERS. P.C. Canaan. Jour. 3oc. Chen. Ir.d. 57, 225-34 (July 1938). (British). A new notkod is suggested for obtaining the specific surface of Bands and of fine powders. Briefly tho procedure iB to measure tho permeability of a small sample tc a liquid of known viscosity and, fron this, to calculate tho specific surface, using an equation given in the paper. Tho equation has been tested over a wide range- of conditions and results are accurate even if the particle else distribu tion is irregular, eo tho new noth ad night well havo application in an industrial laboratory. (C) Paocra on Industrial Poteens. Cancer.,Dermatitis, ata. 36 Hazards FROM G,,5ES IN METAL MINES AND PROTECTIONS AGAINST TMai. B.K. Denny. Mining Teel.. Tech, Paper No. 984, 10 pp. (November 1938). In the past fow yoorB a number of men have been asphyxiated in mines, tunnels an. wells where those occurrences might have boon prevented by a few relatively sim ple precautions. The author gives typical exonploa taken from the flits of the Bureau ol' Mines. Probably meat accidents occur in oxygen deficient atmospheres, in locations where ventilation is poor and where nitrogen and carbon dioxide gases issue from the rock formations. A common mistake is to forget that gas masks cannot make up oxygen deficiency and that special oxygen-breathing appar atus is necessary. Othor causes of asphyxiation are nitrogen fumes from dyna mite; the highly poisonous hydrogen sulfide gAsea which are present in many unde ground operations, chiefly tunnel and caisson work; nnd carbon monoxide, Oood ventilation is the best precaution and should be supplomonted with the proper respiratory equipment proporly used. 37 FLUE GASES LAUNDERED TO PREVENT AIR POLLUTION. U.V. Klcinschmitt. Power Plant Eng. 4, 393-6 (1938). A scrubber ic described that combines atomized spray with centrifugal separation and remove's oust as veil as sulfur dioxide gases. Ic is thought th3t gas elimin atlon as well as dust removal should bo considered in air conditioning. Hi/66-8009782