Mercury Poisoning as a Mining
Hazard.--This is the title of a Bureau of Mines information circular by SARA J. DAVENPORT ANO D. HARRINGTON, which states that an increase in the occurrence of mercury poisoning among workers in mines and allied industries may be expected as the result of growing demands for this strategic metal in war time industries. Mercury vaporizes readily, and small concentrations of its fumes or dust may cause serious physical disturbances which sometimes affect the brain and nervous system of workers according to the Bureau. In mercury mining the most effective way to control and reduce poisoning of human beings is by thorough and adequate ventilation of mines which removes fumes and dust and cools the air. For preparing and purifying the metal, the Bureau recommends the use of airtight furnaces, condensers and retorts, with enough negative pressure to prevent the escape of dust or fumes. In other occupations where mercury is handled, such as in the manufacture of explosives, prevention of mercury poisoning is a matter of "good housekeeping" and sanitation. Every care should be taken to prevent spilling of mercury droplets and to clean it up after it has been spilled. Floors, benches and other fixtures on which dust or droplets may accumulate should be cleaned daily. The main source of mercury is cinnebar, and poisoning may develop in mining from handling ore that contains free mercury, from dust and fumes that escape during retorting the ore and condensing the vapor, and from the handling of liquid mercury. In addition to workers in mines and processing plants, other persons are possible victims of mercurial poisoning including physicists, chemists, physicians, dentists and natural science teachers. Mercury enters the body chiefly by inhalation of dust and vapor and by swallowing as with food, although dust can enter through the skin. Characteristic symptoms are inflammation of the mouth, psychic irritability and muscular tremor with the subsequent varying effects. R. H. O.
Cylinder Columns Carry Shipyard Cranes.--( Engineering News-Record, Vol. 128, No. 9.) Without precedent as a guide, unbraced column supports 93 feet high have been used for overhead cranes at a shipyard where clearances were limited by reason of the desire to utilize piling already in place. The columns are cylindrical in shape