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A new kind of glass which can be precision-machined through the use of ultraviolet light, heat, and hydrofluoric acid to form intricately cut patterns of any desired shape and depth has been developed by the Corning Glass Works, Corning, N. Y.
This new glass is the latest in a series of photosensitive compositions first announced by Corning in 1947 to produce permanent 3-dimensional photographs in glass in a variety of colors. To the new composition, which is a special kind of photosensitive opal glass, an equally new process of chemical machining has been adopted, which produces, without the aid of mechanical tools, lace-like patterns hitherto considered impossible in glass.
The first step in the process is the printing of a design in the glass, using an ordinary photographic negative and ultraviolet light. Development then is accomplished by heating the glass to 1200 degrees Fahrenheit for the required length of time, usually about two hours. At this stage, a milk-white image appears in the otherwise transparent glass.
Next, the glass is immersed in a solution of hydrofluoric acid until the white areas are eaten through and removed, leaving the remaining unexposed glass in the exact form of the original pattern.
By varying the length and intensity of light exposure through the photographic negative, the depth of acid penetration in the glass can be accurately controlled from shallow etching to complete erosion. In this way, sculptured figures or contoured shapes can be made by using a continuous tone negative with proper degrees of shading.
Since chemical machining involves no mechanical stress, patterns, otherwise too complex to reproduce in glass or any other material without long and tedious skilled craftsmen, can be reproduced simultaneously in any number and with photographic accuracy.
Chemical machining is especially suited to perforating holes of any shape having diameters of only a few thousandths of an inch and numbering up to several thousands per square inch. Designs as irregular as lacework can be photoetched as readily as simple straight-line patterns.
The versatility of the process has already been demonstrated in the manufacture of printed electric circuits for electronic instruments. By using a photographic negative, in a single operation, a sheet of glass is cut into multiple pieces, each of proper shape and size, and each having identically etched circuit โข patterns and holes for fastening to a chassis. The pattern thus photoengraved in each piece of glass is filled with conducting metals to form an electric circuit of high precision and durability.
A rapid cure for malaria may be provided by primaquine, a new drug now undergoing extensive field testing by the Army. First tested on volunteer prisoners at the Statesville Penitentary, Joliet, Illinois, in cooperation with the University of Chicago, and later in Nicaragua and at Forts Benning and Knox, the drug gave a high percentage of cures among malaria cases with no subsequent relapse. Several hundred men returning from Korea will be treated with primaquine, while enroute to the U. S. ; if this trial is successful it may be possible to cure malaria which has been suppressed by chloroquine, now used in Korea, without an individual knowing he had contracted the disease.
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