238 A. W. Wright — Cathode Hays and their Effects. 



This confirms the statement of Prof. Bontgen that regular re- 

 flection does not occur, and the theoretical results announced 

 by Jaumann in his remarkable paper, where he shows that 

 diffuse reflection may occur but not specular reflection.* 

 Other objects upon this plate were slips of differently colored 

 glass, ebonite, tin-foil and thin sheet aluminium. The latter 

 having a thickness of about 0'l mm , transmitted the rays so freely 

 that it shows but very faintly upon the negative, and not at all 

 upon the prints from it. The ebonite i-8 mm in thickness 

 ranked next in permeability. The slips of glass (crown) 

 showed apparently no effect dependent upon color, the effect 

 in stopping the rays being evidently dependent chiefly upon 

 the thickness. The tin-foil transmitted the rays somewhat 

 freely, and the impression shows the various little irregulari- 

 ties in its surface. Lead a little more than a millimeter thick 

 was practically opaque. 



Other experiments were made upon the bodies of animals 

 and the human hand. A rabbit, purchased in one of the mar- 

 kets of the city, after an exposure of one hour to the rays, left 

 upon the plate a complete representation of the bony skeleton, 

 the bones of the legs being very sharply and perfectly repre- 

 sented. The region of the lungs was more transparent than 

 the rest of the body, and the heart still more so, being some- 

 what definitely outlined. The cartilages at the base of the ears 

 left a distinct trace, the ears themselves scarcely any. Particu- 

 larly interesting in this photograph were several small round 

 spots which appeared dark in the positive print. These were 

 at once surmised to be shot, and from the indication of their 

 location in the print were readily found and extracted. The 

 mode of death of the animal was not previously known. Simi- 

 lar results were obtained with the body of a rat, the whole skel- 

 eton being shown, with some of the tendons. Organs of the 

 abdominal region were also discriminated to some extent. 



The photograph of the hand shows the bones and their articu- 

 lations very clearly and well defined. On the side of each fin- 

 ger the plexus of nerves and blood-vessels is distinctly shown 

 as it divides into several branches for distribution to the ball 

 of the finger. When the negative is held to the light the hand 

 appears as if modeled in a translucent, luminous material, with 

 the full appearance of roundness and solidity. It is as if it had 

 become nearly transparent, so that the structure of the interior 

 could be seen, not only in respect to the particulars already 

 mentioned, but also with respect to the distribution, or relative 

 abundance, of the blood in its different parts. It may be 

 remarked here that this effect is noticed in many other cases. 

 The pictures are not merely flat shadows, but the partial opac- 



* Longitudinales Liclit., Wied. Ann., lvii, p. 147, 1895. 



