In a second series of experiments by Dr. Wuillomenet a human head was used, but the results were negative in spite of a great intensity of the rays and a long exposure, [§ 82].
161. Fernand Ranwez’s Experiments. Application of the X-rays to Analysis of Vegetable Matter. Comptes Rendus, Apr. 13, ’96. From trans. by Louis M. Pignolet. Sciagraphy can render valuable services in analytical researches and specially in the analysis of vegetable foods where they will show the most usual adulterations consisting of mineral substances.
Bas-relief Sciagraph, [§ 159], by Prof. Dayton C. Miller.
This method offers several advantages for small samples of the substances can be examined. The samples are not chemically changed. A great number of tests can be made in a short time. Lastly, the sciagraph obtained affords a permanent record.
The tests were made on samples of adulterated saffron composed of mixtures of pure saffron and saffron coated with sulphate of barium. A sciagraph taken with an exposure of three minutes showed scarcely visible imprints of the pure but strong impressions of the adulterated. See sciagraph of pen, (mineral) in holder, (vegetable), in cut at upper part of p. [164], which also shows the graphite in a wooden pencil.
162. Errera’s Experiment. Action of the X-rays on Phycomyces. Hertz Waves and Roentgen Rays Not Identical. Comptes Rendus, March 30, ’96. From trans. by Louis M. Pignolet.—Phycomyces Nitens, when submitted to the asymmetrical action of Hertz electric waves, became curved, according to Hegler. Errera found a Phycomyces was not affected by the X-rays, thus denoting an absence of Hertz waves in the rays. Credit for the above result is due to L. Errera, from experiments made at the Laboratoire Physique and the l’Institut Solvay (Université de Bruxelles).
163. Gossart, Chevallier, Foutana and Uruanni’s Experiment, in Conjunction with J. R. Rydberg. No Mechanical Action of X-rays. Comptes Rendus, Feb. 10, Mar. 23, Apr. 13, ’96. From trans. by Louis M. Pignolet.—The former party alleged that radiations from a discharge tube caused a cessation of the rotation of the vane of the radiometer. J. A. Rydberg was not inclined to confirm such action. A. Foutana and A. Uruanni made experiments and concluded that the action was due to an electro-static force, having noticed that a Leyden jar would also produce such effect. The author made some experiments to determine the matter in reference to X-rays at a distance outside of the electro-static field. The rays would neither stop the vanes nor cause them to rotate. He made some other experiments to detect whether there was any direct mechanical power possessed by the rays; but if any, it was exceedingly feeble.
T. C. Porter made some experiments at Eton College, (Nature, June 18, ’96,) which confirmed the above results, finding that the radiometer is entirely inert to the Roentgen rays, whether they be from a properly electrically screened hot or cold tube. He distinguished between the caloric conditions, for he found that, not only will reduction of temperature vary the penetrating power of the rays, [§ 135] and [152a], but also will an increase of temperature.
164. Battelli’s Experiment. X-Rays Within Discharge Tube. Nuovo Cimento, Apr., ’96, p. 193; Elect. Rev., Lon., June 12, ’96.—Shortly after the announcement of the discoveries of Lenard and Roentgen, it would have been considered strange to assert that X-rays may exist inside of the discharge tube. Battelli certainly correctly infers, that inasmuch as X-rays apparently originate from the point where a material object is struck by the cathode rays, [§ 115], it would follow that when the said object is within the vacuum space, X-rays are propagated before they reach the glass wall of the discharge tube. It has already been noted (DeMetz, [§ 63a]) that photographic action may be produced within the discharge tube. Battelli has confirmed this, not by a crude experiment, like that (failure) of some authority in England, but by a series of severe tests, leaving no doubt as to the production of photographic action. He discovered in connection with several subordinate phenomena that among the rays capable of producing a photographic impression within the discharge tube, some were deflected by a magnet and others were not, from which he concluded that X-rays may exist inside the tube, in conjunction with cathode rays, before collision with the anti-cathode. The experiment consisted in deflecting the rays by a magnet, the film being in the path that the rays would have had without a magnet. There was also a film in the path of the deflected rays. Photographic action was produced upon both. He varied the vacuum. Photographic action began at 3-10 mm., had its maximum at 1-70 mm., after which it remained constant. No photographic action was obtained upon a film placed within the tube opposite the anode, except in one case where it was exceedingly weak. Lenard continually inferred that there must be two kinds of cathode rays. [§ 75]. Battelli has certainly sifted the two rays apart and thus proved Lenard’s conjectures. [§ 61b], p. [47]. The Elect. Rev., Lon., pays tribute to Battelli, by offering the following opinion: “We have no hesitation in saying that Battelli, by means of interesting and ingenious experiments, has made the greatest advances in the theory of the X-rays since their discovery by Roentgen.”