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POPULAR SCIENCE REVIEW. 
iaside to receive it, and on the top of the rod is a brass ring about 1^ inch 
deep, in the top of which is a female screw, in which the jointed top is 
screwed that carries the camera. D is the brass top, with the joint J, and 
a screw to insert into the end of the rod, which can he heightened or lowered, 
and fixed by the screw G. F is a tube-line, with India-rubber to fit the 
opera-glass camera, for which a telescope might be substituted. When the 
tripod is used as a walking-stick, there is a stick-head with a screw attached 
to screw into the top of the rod, and a thin tube to hold the legs'together 
at the bottom, where the diameter of the legs is f inch. The whole is 
stained and varnished, and cannot, without a close inspection, be distin- 
guished from an ordinary walking-stick. 
Imiar Photography , — The Mechanic's Magazine, in an article on Mr. 
Warren de la Rue’s lunar photographs, says : In instantaneous photography 
the colour and composition of the glass forming the lenses afiect the results, 
for all glasses are opaque, more or less, to a portion of the visible rays of the 
spectrum. The same difficulty besets photographic work with a reflecting* 
