COMPOSITE PORTRAITS, STEREOSCOPIC MAPS 265
for me by my cousin, long since dead, R. Cameron Galton, in the Proceedings of the Royal Geographical Society [18] of that year. I cannot fully understand why stereoscopes do not hold a higher position in popular estimation than they do ; it may be partly due to two causes-to the fact that the two eyes are unequally operative in a larger proportion of persons than might be supposed, and to the cost and unwieldiness of the usual stereoscope. Compound lenses give better and wider images than plain ones, but for common purposes I find that plain ones, mounted as in an eyeglass, serve quite well enough. Those I generally use are cheap things, mounted in a strip of wood.
I wished to obtain a map that should have the effect of a model, so suitable models were procured and photographed stereoscopically. The result was a perfect success. An unexpected result occurred when a pure white plaster cast was treated in this way, for it wholly failed to give the required appearance of a solid, but if grains of dust were sprinkled over it, much more if names were written on it, the stereoscopic effect appeared in its full strength. Good models, and therefore stereoscopic maps made from them, give a far better idea of a mountainous country than any ordinary map can do, however cleverly it may be shaded. Map-makers might well pay some attention to stereoscopic maps and to providing cheap eyeglasses with which to view them.
