The accompanying picture, p. 6, marked Terry’s Sciagraph, Fig. 1, is a sciagraph of pieces of different materials named as in the following list, taken by Prof. N. M. Terry of the U.S.N.A., see also p. 127. “1, rock salt, 0.6 inch thick; 2, cork, 0.4 inch thick; 3, quartz, 0.45 inch thick, cut parallel to optic axis; 4, verre trempe, 0.4 inch thick; 5, glass, 0.7 inch thick; 6, chalk; 7, Iceland spar; 8, mica, very thin; 9, quartz, over a square piece of glass; 10, aluminum foil, [_a_] four thicknesses, [_b_] two thicknesses, [_c_] one thickness; 11, platinum foil; 12, tourmaline; 13, aragonite; 14, paraffine, 0.4 inch thick. 15, tin foil, [_a_] one thickness, [_b_] two thicknesses, [_c_] three thicknesses; 16, rubber insulated wire; 17, electric light carbon; 18, glass, 0.32 inch thick; 19, alum., 1.4 inch thick; 20, tourmaline; 21, gas coal; 22, bee’s wax; 23, pocket-book, 10 thicknesses of leather; 24 coin in pocket-book; 25, key in pocket-book; 26, machine oil in ebonite cup; 27, ebonite, 0.25 inch thick; other samples have given very faint shadows like wood and leather; this was polished; 28, wood, 0.2 inch thick; 29, steel key.” _Elect. Eng._, N.Y. 134_a_. HODGES’ EXPERIMENT. ILLUSTRATION OF PENETRATING POWER OF LIGHT. _Elec. Eng._, N.Y., March 4, ’96. Attention has been invited in the scientific press to the penetrating power of heat rays and of light rays of low refrangibility. In conjunction with this, let it be remembered that the photographic plate has the property of being impressed practically, only by rays having a higher refrangibility than red. It would be natural, therefore, to conclude that if the spectrum could be turned around, the photographic impression might be produced through opaque bodies. This perhaps, was the kind of reasoning which prompted Mr. N. D. C. Hodges, formerly editor of _Science_, to perform an experiment, the gist of which consisted in attesting the permeability of rays of light which had been passed through fuchsine. Christiansen, Soret and Kundt performed experiments with an alcoholic solution of this material and found that the order of the colors in the spectrum was somewhat reversed, namely, violet was the least refracted, then red, and then yellow, which was the most refracted. Mr. Hodges used a pocket kodak, carrying a strip for twelve exposures. This camera was placed in a closely fitting pasteboard box. Thus protected, some portions of the film were exposed to sunlight, so far as it could penetrate the end of the pasteboard box, while other exposures were made with a prism, on the end of the box, containing an alcoholic solution of fuchsine. The portions of film exposed to the anomalous rays produced by the fuchsine solution were fogged, while the control experiments with ordinary light showed none. The anomalous rays must have penetrated the pasteboard, and probably the wood and leather of which the camera was made.