12 
2. Variable star in Vela, several photographs, show- 
ing the variation of the star. 
3. Specimen plates of the Astro-photographic Cata- 
logue and Chart work at the Cape of Good Hope 
Observatory. 
Nos. 11 and 12 exhibited by Columbia University Observa- 
tory, J. KoyRees, Director: 
PHY SiCs. 
Es 
In CHARGE OF WILLIAM HALLOCK. 
1. Dippin PENTANE Lamp. Exhibited by Alexander C. Hum- 
phreys. The Standard of illumination adopted in Lon- 
don. It is approximately equal to to candles. 
2 POLARISCOPE, special form designed by Prof. A. M. Mayer. 
Exhibited by the Department of Physics, of Columbia 
University. 
3. Two Mirror Hetiostat. Designed by Prof. A. M. 
Mayer. Exhibited by the Department of Physics, of 
Columbia University. 
4. APPARATUS FOR SHOWING THE VIBRATION OF A STRING. 
Designed by Prof. W. L. Robb. Exhibited by O. N- 
Rood. 
APPARATUS FOR VoICcE ANALysis. A modification of the 
Keenig apparatus, with photographic record. Accom- 
Sti 
panied by a set of corresponding organ-pipes. 
6. PHoToGraApus of the same vowel in typical voices. 
7. PHoroGraPus of different vowels in the same voice. 
8. APPARATUS FOR PHOTOGRAPHING THE VOCAL CorDs IN 
Action. A combination of laryngoscopic mirror, spe- 
cial Camera and Shutter. 
