How? or, Spare hours made profitable for boys and girls (1887)
Holbrook, Kennedy · New York, Worthington co. · leaf 150
room darkened. If, now, the beam CAMERA OB SCUBA. 145 of light entering the room by this hole be intercepted bya sheet of white paper, held at a small distance from thehole, an inverted image of objects without will be seenupon the paper. By placing a small convex lens over thehole this image is… … tion either nearer to the hole or further from it, the imagebecomes indistinct and confused. At the point of great-est clearness the image is said to be focused. Such beingthe principle of the camera, it is evident that in practicethe instrument may assume many forms, provided alwaysthat it…
Handicraft · Amusements
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