778
THE POPULAR SCIENCE MONTHLY.
interest by its application to dry-plate photography. When we return to the classical investigation of Lenard mentioned in the beginning of this article, we are impressed by an apparently crucial
Röntgen Picture of a Hand after Lengthened Exposure.
From The New York Medical Journal.
experiment which he describes in regard to the existence of an ether. He caused the cathode beam to pass out of his high vacua through an aluminum window into another tube about three feet
