250 IOWA ACADEMY OF SCIENCE 



1900 



Chin sen and v. Bronk (New phenomena in the field of Physics; 

 self published, Berlin). 



Himstedt (Ann. d. Phys., 4, 531), Some experiments with 

 Becquerel and X rays. 



Smolders (Journ. Phys. Chem., 4, p. 423), The allotropic forms 

 of selenium. 



1901 



Block (Compt. Rend., 132, 914), Action of Radium rays on se- 

 lenium. 



Giltaij (Phys. Zeits., 1901, p. 675), Apparatus for the demon- 

 stration of the light-sensitiveness of selenium. 



Giltay (Meehaniker. 1901. p. 243), Apparatus for demonstrat- 

 ing the photophon. 



Massmi (Eclair, e'lectr., 29, p. 68), The effect of electromag- 

 netic waves on the resistance of selenium. 



Ruhmer (Phys. Zeits., 2, p. 325), The talking arc with sele- 

 nium. 



Ruhmer (Phys. Zeits., 2, 498), The photographone. 



Ritrhmer (Meehaniker, 9, 468 and 2), Simons photophone. 



Ruhmer (Meehaniker. 9, 41), The preparation of light sensi- 

 tive cells. (9. p. 88), The talking arc and light telephony. 



Ruhmer (Meehaniker, 9, 1901, p. 13), Seeing at a distance, etc. 



Simon (Phys. Zeits., 2, p. 253), Light telephony with the speak- 

 ing arc. 



1902 



Cciblyn (Compt, Rend., 135, 684), Seeing at a distance electri- 

 cally. 



Kom (Miinchen Ber., 37, 39), An experiment with electrical 

 photography at a distance. 



Kom (Electroteeh. Zeits., 23, 454), An apparatus for distance 

 photography. 



Pochettino (Beibl. z. d. Ann.. 27, 854), The influence of low 

 temperatures on the resistance of selenium and the re- 

 sistance change by light. 



