730 



SCIENCE. 



LN. S. Vol. III. No. 72. 



sugar plate. The Crookes tube was sus- 

 pended 6;^ inches above the plates and an 

 exposure of forty minutes was given. 



The conditions under which the two 

 sugar plates were placed were therefore 

 identical and the results obtained compara- 

 ble. On developing the photographic plate 

 it was found that both sugar plates had 

 permitted the X-raj'S to pass through suffi- 

 ciently freely to form clear and well defined 

 pictures of the metallic disks. 



The figures and inscriptions on the alu- 

 miniu.m medals were discernible in both in- 

 stances, and the outlines of both the alumin- 

 ium disks and of the silver coins were a,lso 

 well marked. 



The negative, however, showed unmis- 

 takably that the amorphous sugar is more 

 transparent to the X-rays than the crj'stal- 

 line modification. In the former case the 

 background proved to have an even and 

 darker hue, showing that X-rays had passed 

 through fi-eely and evenly. In the latter 

 case the background was less dark and of 

 a rather mottled appearance, in some places 

 exhibiting apparently a faint outline trac- 

 ing of the crystalline structure beneath 

 which it had rested. This fact may be of 

 interest in view of the mooted question con- 

 cerning the power of diffusion and refrac- 

 tion of the X-rays. 



In this connection it may not be amiss 

 to also refer, briefly, to some tests made to 

 ascertain whether or no the X-rays exercise 

 any influence on polarized light. To this 

 end a tube was made of aluminium, 200 

 mm. in length and 31 mm. in diameter; the 

 walls were 2 mm. thick. This tube was 

 filled successivelj^ with solutions of sucrose, 

 dextrose, levulose and rafiBnose. 



This tube with its contents was placed in 

 a sugar polariscope ; a ray of light was per- 

 mitted to pass through the tube and the 

 deviation of the polarized light j>roduced 

 by the solutions was noted. The polari- 

 scope with the filled tube was then placed 



underneath a Crookes tube in such a man- 

 ner that the tube was directly in the path 

 of maximum intensity of the X-rays, i. e., in 

 the path of the cathode rays, so that the 

 rays would pass through the tube practically 

 at right angles to the beam of polarized 

 light which traversed the tube longitu- 

 dinally. 



The times of exposure given varied; seven 

 minutes for the sucrose solution, ten min- 

 utes for the levulose and the raffinose solu- 

 tion and fifteen minutes for the dextrose 

 solution, but in no instance was any de- 

 viation of the raj' of polarized light notice- 

 able. The polarization of the solutions 

 were : 



Sucrose, + 49.9 



Raffinose, +15.3 



Dextrose, + 7.2 



Levulose, — 8.8 



Of course these tests alone are not suffi- 

 cient in number or kind to permit the draw- 

 ing of any conclusive inference as to whether 

 the X-rays influence the plane of polarized 

 light or not, but they do establish the fact 

 that, under the conditions under which these 

 tests were made, no such influence was 

 exerted. Ferdinand G. Wiechmann. 



THE X-RAl'S IlSf 3IEDICINE AND SUBQEBY. 



On Api-il 22d I succeeded in applying the 

 X-rays to the diagnosis of disease in such a 

 manner as to make it seem that a very 

 wide fleld was open to medical as well as 

 to surgical investigations by means of the 

 X-ray. 



Using a ' focussing ' tube powerfully 

 di'iven, I found it quite possible to cause 

 calcium tungstate to fluoresce, even though 

 a human trunk or head be intei-posed be- 

 tween the tube and the fluorescing screen. 



Further, it became evident that the back- 

 bone, the ribs, the bones of the members, 

 and the outline of the skull and of the up- 

 per portion, at least, of the pelvis could be 



