167. In the same paper Prof. Thompson showed conclusively that there is a diffuse reflection of X-rays. [§ 81] and [103]. A curious experiment consisted in his obtaining dust figures, [§ 36]. by the discharge of an electrified body by X-rays. In another experiment he caused reflection of the rays from the surface of sodium located in a vacuum. The amount reflected was a minimum for normal incidence and increased at oblique incidence.
168. Prof. Oliver J. Lodge, F.R.S., reported in The Electr., Lon., June 5, ’96, further detail experiments in the line set out in [§ 113]. He proved conclusively, as stated by the editorial in The Electrician, that a positive charge has increasing effect upon the ray-emitting power of the surface exposed to the cathodic radiation.
169. At Eton College, T. C. Porter (Nature, June 18, ’96) confirmed the experiments of others by showing that the blackened face of the thermopile connected with a very sensitive galvanometer was not influenced in any manner by X-rays.
170. Prof. William F. Magie, of Princeton, N. J., made a careful experiment in relation to diffraction. Princeton College Bulletin, May, ’96. The experiment would certainly prove that if X-rays are due to vibrations, the latter are of a different order from those occurring in light rays, for the slits exhibited light diffraction very well, but there was no evidence, by a widening of the image on the plate, that X-rays had been diffracted in the slightest degree. [§ 110] and [110a].
171. Prof. Haga, of Groningen University, at the suggestion of Mr. J. W. Giltay, (Nature, June 4, ’96,) made some very crucial tests, with numerous precautions, in reference to the action of X-rays upon selenium, and the results were so positive that they thought that a practical application could be made by using selenium for detecting X-rays, both qualitatively and quantitatively. In repeating the experiments, it must be borne in mind that one half hour or so is required for selenium to return to its former degree of ohmic resistance after being struck by light or heat or X-rays.
Total number of § § to this place, 199.
CHAPTER XIII
A few Typical Applications of X-rays in Anatomy, Surgery, Diagnosis, etc.
200. Hogarth’s Experiment. Needle Located by X-rays and Removed. The Lancet, Lon., Mar. 28, ’96.—Dr. Hogarth is the medical officer of the general hospital, Nottingham. A young woman was suffering with a pain in her hand near the metacarpal bone of the ring finger. A slight swelling existed. Ten weeks before, a needle had entered the palm while washing the floor. It had entered at the base of the fifth metacarpal bone. Chloroform had been given and an incision made, but no needle found and its presence doubted. A sciagraph was taken and the needle was accurately located and the next day removed.