Characteristics of striæ in optical glass . Fig. 14.—Sample of Fig. 13 viewed flatwise use may be seen from the photograph (Fig. 9) of the striae in a six-power binocular, which was among those submitted by the SignalCorps of the United States Army to this Bureau for test. Thestriae in the left barrel of this binocular are prominent. There wasan observable amount of scattered light about the image of anartificial star when an auxiliary telescope was used, but withoutsuch an aid the images produced by both barrels were equally. Fig. 15.—(a) Without glass; (6, c) viewed flatwise through rolled w
Characteristics of striæ in optical glass . Fig. 14.—Sample of Fig. 13 viewed flatwise use may be seen from the photograph (Fig. 9) of the striae in a six-power binocular, which was among those submitted by the SignalCorps of the United States Army to this Bureau for test. Thestriae in the left barrel of this binocular are prominent. There wasan observable amount of scattered light about the image of anartificial star when an auxiliary telescope was used, but withoutsuch an aid the images produced by both barrels were equally. Fig. 15.—(a) Without glass; (6, c) viewed flatwise through rolled windowplate {same as Fig. 10); (d, e,f) edgewise through same plate good so far as the unaided eye could distinguish—far better thanthose obtained with many binoculars in which the amount ofstriae present was negligible. A lot of prisms and lenses, rejected after polishing, were tiu-nedover to this Bureau by the optical shop annex of the Naval GunFactory at Rochester. These prisms were discarded on account Smith, Bennett,!Merritt J Stri(B in Optical Glass 85 of striae, bubbles, and scratches, the polish and workmanship inall cases being above criticism. All of the prisms shown in Fig. 3were taken from this lot of rejects, the prints to the left beingshadowgraphs of the striae in the prisms. Dr. Zwillinger, of theoptical shop annex, loaned the authors a testing frame into whichthe different parts of a biftocular could be fitted at pleasure. Byinserting single, discarded parts in an otherwise first-class optical KALEV
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Keywords: ., bookcentury1900, bookdecade1920, bookidcharacterist, bookyear1920
