OCR Text |
Show i Optical Glass Made by Uncle Sam Is . V 'f A JA fir V 4 My; - ii 3 P - - ' ji ,.i if J ' - -" "".'l :l 1 i -i 3 5 tl ! . U2 - .ww -.w i-.a-.u-w-u.-. ..-TrgT.aj iJ The art of making optical glass, which was practically unknown in the United States prior to the World war, is being developed at the bureau of standards in Washington. This remarkable photograph shows a stop wat(h taken through a piece of optical glass five inches thick, while on the left is some of the glass before being polished. |