Rensselaer Union, Volume 2, Number 36, Rensselaer, Jasper County, 2 June 1870 — Suggestions to Those Using Stereoscopes. [ARTICLE]

Suggestions to Those Using Stereoscopes.

A correspondent of the Elmira Advertiser furnishes that paper with the following: Ist. Examine the pictures you purchase, very carefully, to see if they are true stereoscopic views. The two pictures on each card should not be exactly alike, but should be taken at a slightly different angle. This “ parallax,” as we say in astronomy, gives the effect of “ solidity ” to the view. To test this, take some object in the foreground and see how it ranges with some object in the background in both views If the angle be the same, then the effect will be inferior. 2d. Unscrew the frame containing the two lenses, and turning it around so as to bring the former face to the back, screw it on again. The instrument will not look quite so workmanlike, but to the eye at least is much easier. I can use my stereoscope without pain, while formerly one or two views at a sitting was the extent my eyes could endure.