50, 100 and 150 Years Ago; March 1997; Scientific American Magazine; by Staff Editor; 1 Page(s)

MARCH 1947 The problem of giving automatically reproduced form letters that individually typed look has found a solution in a device called the Flexowriter Automatic Letter Writer. Operated by means of a perforated paper tape 7/8-inch wide, it consists of an electric typewriter, an automatic perforator and an automatic writer. In preparing the form letter, the operator types manually the date and the name and address of the recipient. Then a switch is thrown, and the automatic writer takes over, controlled by the previously prepared tape.

Fouling of lenses and other optical parts of instruments used in the tropics was until recently a serious problem, particularly in the Pacific areas. The way this hindrance was checked has now been revealed. Metal foil is treated with radium compounds to give it an alpha-ray emission equivalent to about 15 micrograms of radium per square inch, and narrow strips of the foil are mounted around the lenses.