246 IOWA ACADEMY OP SCIENCE 



Carpenter L. (Nature, 24, 491), The use of the photophone. 



Giltay (Nature, 25. 124), An audible photometer. 



Kalischer (Rep. d. Phys., 17, 563), Photophon without bat- 

 teries. 



Mercadier (Compt. Rend.. 92, 1407, 1881), Effect of tempera- 

 ture on photophonie receivers. 



(Compt. Rend., 92, 789), Construction of photophonie re 

 ceivers. Also p. 705, C. R. 



Molera and Cebrian (Engineering, 1881, p. 358), Conical form 

 of selenium cells. 



Moser (Soc. Telegr. Engr., 11, May, 1881), The selenium photo- 

 phon. 



Moser (Phil. Mag., 12, 212), The microphonic action of selenium 



cells. 

 Sirks (Beibl. z. d. Ann., 5, 526), The change of resistance of 



selenium. 

 Spring (Bull, de 'lAcad. des Scienc. de Belg., 2, 88, and Beibl. 



5, 854), The coefficient of expansion of selenium. 



Thompson, S. P. (Eng., 1881, p. 96; and Phil. Mag., 11, 286), 

 The use of the conical mirror to illuminate selenium. 



Thompson, S. P. (Chem. News, 43, p. 43), The photophone. 



Tomlinson (Nature, 23, 457), Photophone. 



Fitlal (Moniteur de la photogr., 1881, p. 11), Selenium pho- 

 tometer. 



Borntrager (Ding, pol., J. 242, 55), Preparation of metallic 



crystals by sublimation. 



1882 



Troost (Compt, Rend., 94, 1508), Boiling point, 



Kienlen (Bull. Belg. Akad., 37, 440), Method of extraction. 



1883 

 Assche (Compt. Rend.. 97, 830), A means of isolating heat and 

 light radiations. 



Bidivell (Phil. Mag.. 15, 31), Resistance of selenium cells. 



Fritts (Sill. Am. Journ., 26, 465; and Lum. Eleetr., 15, 226\ 

 Light sensitive selenium cells. 



