Characteristics of striæ in optical glass . v5r/Rfify/ Fig. 7.—Projection of the stricB in a lens The distances must be adjusted to suit the focallength of the lenses. A coUimating lens may be usedif it be desired to pass a plane wave through the lens Smith, Bennett,!Merritt J Strice in Optical Glass3. CHARACTERISTIC STRI^ 8l. Fig. 8.—Strice in binocular objective The striae of Figs, i and 2 are typical of the sort which resultwhen glass is melted, stirred, cooled, broken out, then reheated,paddled, and molded. The heaviness of the striae is determinedby factors which are beyond thescope of th
Characteristics of striæ in optical glass . v5r/Rfify/ Fig. 7.—Projection of the stricB in a lens The distances must be adjusted to suit the focallength of the lenses. A coUimating lens may be usedif it be desired to pass a plane wave through the lens Smith, Bennett,!Merritt J Strice in Optical Glass3. CHARACTERISTIC STRI^ 8l. Fig. 8.—Strice in binocular objective The striae of Figs, i and 2 are typical of the sort which resultwhen glass is melted, stirred, cooled, broken out, then reheated,paddled, and molded. The heaviness of the striae is determinedby factors which are beyond thescope of this paper; but the striaeconsist usually of veins or cordswhich vary greatly in prominenceand density. In some cases they arelight and scattered, as in Fig. 2 andin the lower prisms of Fig. 3, while inothers they are heavy and prominent,as in Fig. i, or may be denselypacked, like tubes of vermicelli, aswith the upper prism of Fig. 3. At times it has seemed desirable toroll optical glass into plates in the same way in which ordinaryplate glass is rolled, and in such cases the ordinary cords or veinsare pressed out into sheets parallel to the faces of the rolledplate. Fig. 10 shows the striae in two such plates, the one exhib-iting the heavier striae being a pieceof ordinary green-colored window plateglass with rectangu
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Keywords: ., bookcentury1900, bookdecade1920, bookidcharacterist, bookyear1920
