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Page:Popular Science Monthly Volume 89.djvu/344

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330

��Popular Science Monthly

��Making the Scallops on Plate Glass

���The Tool Grasps the Edge of the Glass Plate and Bites It Off With a Tooth or Point

WILLIAM SPANGLER, a resident of Illinois, has invented an im- proved glass-chipping tool which has for its purpose the ornamentation of plate glass by scalloping. The ordinary glass-chipping tool can be used on glass of one thickness only, and when a plate of another thickness is to be chipped another tool must be employed. The tool grasps the edge of the plate between a bearing point and a bit and bites it off with a tooth, or point, provided for the purpose. In order that the same tool may operate successfully with varying thicknesses of glass it is necessary that the space between the bearing I)oint and the bit be adjust- able in two directions — transversely of the edge of the glass and longitudinally of the handle of the tool, so that the bearing point shall im])inge the glass at varying <listaiices from the edge.

The invention referred to provides for tills double ad- justment of the jaws.

��How Heat Is Measured with the Eye

NOW that man has succeeded in obtaining artificial heats that al- most rival the intensity of the sun, the accomplishment has made the demand upon him that, in harnessing this terrific heat for industrial purposes, he shall devise some means of measuring it. For many years after electric heat was known and used industrially the exact tempera- tures which existed were only guessed at. Recently, an instrument known as the thermo-electric pyrometer has come into use, but this ingenious type of thermom- eter has the serious limitation that it will melt when the temperature has passed a certain point. The latest development in heat-measuring devices is an optical instrument, which, while it is placed in operation many feet from the heat source, will measure the tempera- ture with a fine degree of accuracy.

The "sight pyrometer," as it might be called, really takes up the measurement of temperatures where the ordinary pyrometer leaves off. It can safely and accurately measure heat at temperatures as high as 7200 degrees Fahrenheit. The

���MLasurinu Htat-Trcating Temperatures With the "Sight Pyrometer" Many Feet from the Heat Source

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