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.
The above tests were made by Albert Buquet and Albert Gascard, at the Cabinet de Physique de l’École des Sciences de Rouen.
The half-tone on lower half of adjacent page, 164, was taken from a sciagraph by Prof. Dayton C. Miller, of Case School of Applied Science. The differences of opacity are proved, because all were of same thickness and exposed simultaneously.
Prof. Sylvanus P. Thompson (The Elect., Lon., May 18, ’96) confirmed the above, and also found that, although the diamond is more transparent than glass, it is more opaque than block carbon or graphite.
Mineralogists are thus enabled to submit minerals to the X-ray test in making analyses.
157. Dufour’s Experiment. Inactive Discharge Tubes made Luminous by X-rays. Comptes Rendus, Feb. 24, ’96. From trans. by Mr. Pignolet.—He observed that very small and sensitive Geissler tubes phosphoresced when exposed to X-rays. [§ § 22], [23].
158. Beaulard’s Experiments. Non-Refraction of X-rays in a Vacuum. Comptes Rendus, Mar. 30, ’96. From trans. by Louis M. Pignolet. With prisms of ebonite, F. Beaulard held that no decided deviation could be observed within the vacuum.
159. Carpentier’s Experiment. Sciagraph Showing the Parts in Relief on a Coin. Comptes Rendus, Mar. 2, ’96. From trans. by Louis M. Pignolet. An imprint of a coin stamped upon a thin piece of well annealed aluminum by pressing the coin against the aluminum, was reproduced in a sciagraph. The raised parts of the coin were scarcely 8/100 of a millimeter high. The aluminum was 5/10 millimeter thick. This result is admirably represented by the sciagraph of an aluminum medal on page 166, taken by Prof. Dayton C. Miller, of Case School of Applied Science, Elect. World, N.Y., Mar. 21, ’96, who also made a sciagraph of a copper plate 1/4 inch thick having blow holes which appeared in the picture, but they could not be detected by light, serving to illustrate an application of the new discovery in testing the homogeneity of metals.
160. Wuillomenet’s Experiments. Transparency of the Eye to the X-rays Determined by Sciagraph of Bullet Therein. Comptes Rendus, Mar. 23, ’96. A sciagraph taken with an exposure of three hours showed perfectly a lead shot introduced into the vitreous media of the eye of a full grown rabbit. Therefore the opacity of the media of the eye was not absolute.