This agrees with Bleunard who found that colors seemed to have no influence on the passage of the rays as water colored with various aniline colors offered no more resistance than when pure. From trans. by L. M. P. _Comptes Rendus_, March, ’96. A. and L. Lumière (_Comptes Rendus_, Feb. 17, ’96,) observed that the X-rays act in the same manner upon colored photographic plates rendered sensitive to various regions of the spectrum. Thus, plates sensitive to red, yellow and green gave exactly the same impression, provided they had the same general sensibility to white light. While this may not be accurately so, it illustrates that materials are penetrated by X-rays independently of the laws of color. 155. MESLANS. CHLORINE, IODINE, SULPHUR, PHOSPHORUS, COMBINED WITH CERTAIN COMPOUNDS, INCREASE OPACITY TO THE X-RAYS (_Comptes Rendus_, Feb. 10, ’96. From trans. by Louis M. Pignolet.)—Carbon in its various forms was found to be very transparent, also organic substances containing, besides carbon, only the gaseous elements hydrogen, oxygen and nitrogen; but this transparency was far from uniform. Organic substances,—ethers, acids, nitrogenized compounds (_corps azotes_),—were easily traversed by the rays; but the introduction of an inorganic element, as particularly, chlorine, sulphur, phosphorus, and, above all, iodine, renders them opaque. § 82. This occurs also with sulphates of the alkaloids. Iodoform, the alkaloids, picric acid, fuchsine and urea are very transparent. Metallic salts are very opaque, but this varies with the metal and the acid. Bleunard went further into details. The opacity of solutions of salts increased with the atomic weight of the metal and of the metalloid. Water was easily traversed by the rays. Solutions of bromide of potassium, chloride of antimony, bichromate of potash offered considerable opposition to the passage of the rays. Solutions of borate of soda, permanganate of potassium were easily traversed. The liquids were held in paper boxes. The experiments above related were conducted by Maurice Meslans at l’École de Pharmacie de Nancy. [Illustration: FROM SCIAGRAPH OF PENCIL, KEY, FOUNTAIN-PEN, AND COIN. § 161. By Prof. McKay, Packer Institute. ] [Illustration: FROM SCIAGRAPH BY PROF. MILLER. § 156. 1. Real diamond. 2. Paste. 3. Glass. 4. Real diamond mounted in gold ring. ] 156. BUQUET & GASCARD’S EXPERIMENTS. ACTION OF THE X-RAYS UPON THE DIAMOND AND ITS IMITATIONS; ALSO UPON JET. _Comptes Rendus_, Feb. 24, 96. From trans. by Louis M. Pignolet.—Sciagraphs taken by the X-rays showed that diamonds became transparent, and their shadows disappeared with long exposures; but imitation diamonds remained opaque under the same conditions. Jet was distinguished from its imitations by the same method. The diamond and jet cast clearer shadows on a fluorescent screen than their imitations.