Volume 1

Radiography and radio-therapeutics / by Robert Knox.

  • Knox, Robert, 1868-1928.
Date:
1919-
Catalogue details

Licence: In copyright

Credit: Radiography and radio-therapeutics / by Robert Knox. Source: Wellcome Collection.

    192/544 (page 150)
    Fig. 121.—Diagram to illustrate the principle of Wheatstone’s reflecting stereoscope. (From Ency. Brit.) K K, right and left eyes ; S S S, mirrors ; P P, objects in position ; a b, picture on left side ; b1 a1} picture on right side ; 3 2 1, corresponding points on retina ; A L B, object as seen in relief in mirrors ; b, picture seen by left eye in position B, and image on retina at 3 ; c, seen at L R, and retinal image at 2 ; a, seen at A, and retinal image at 1 ; a1} seen at A, and retinal image at 1 ; c1} seen at R L, and retinal image at 2 ; bv seen at B, and retinal image at 3. stereoscope which generally holds tl Another form of stereoscope which is of great value in X-ray work is that introduced many years ago by Sir David Brewster. The instrument is very convenient for the inspection of reduced pictures of stereoscopic radiographs. These are readily produced in a reduc¬ ing lantern. For small objects, such as fingers, wrists, temporal bones and accessory sinuses, the pictures may be produced on small plates, lantern size, directly from the sub¬ ject. By means of a simple plate¬ changing device the two pictures may be obtained on one plate. These may then be inspected with a Brewster stereoscope. The principle of the Brewster stereoscope is explained by the diagram on page 151. This form of instrument may also be used for the inspection of stereoscopic illustrations in books by removing the portion of the plates or prints. Fig. 122.-—Wheatstone stereoscope. The modified Scott-Dean pattern. (A. E. Dean.) Pirie Stereoscope for the Examination of X-Ray Negatives. —The Pirie stereoscope is arranged on entirely different lines from the instruments which have been heretofore employed for the examination of stereoscopic X-ray negatives. Instead of using reflecting mirrors, a double