THE STEREOSCOPE.
Sir David Brewster, inquiring into the history of the stereoscope, finds that its fundamental principle was well known even to Euclid; that it was distinctly described by Galen fifteen hundred years ago; and that Giambattista Porta had, in 1599, given such a complete drawing of the two separate pictures as seen by each eye, and of the combined picture placed between them, that we recognize in it not only the principle, but the construction, of the stereoscope.