6 
and can be reached by ascending the stairs at the rear of the 
Library. 
If the evening is clear an opportunity will be given visitors 
to the Observatory for viewing some of the celestial objects. 
12. PHOTOGRAPHS OF ICED BAR AND LONG TAPE BASE AP- ~ 
PARATUS, devised and exhibited by Prof. R. S. Woodward. 
DEPARTMENT ORVEEYSICS. 
In charge of Prof. William Hallock. 
13. SPECTROSCOPE, with double micrometer slit and scale-tube, 
with movable slit to locate any special part of the spectra, 
for purposes of comparison; also an adjustable slit in the 
ocular to screen out all the colors except the special one it is 
desired to observe; also glass tanks, absorption-cells, etc. 
The whole intended for color photometry and color compari- 
sons. 
14. MITSCHERLICH PENUMBRA (half-shade) SACCHARIMETER, 
for the quantitative determination of sugar solutions by the 
rotation of the plane of polarization of the light, as well as 
other measurements in polarized light. It is provided with a 
special lamp, and two tubes of different lengths for the solu- 
tions to be tested. 
15. A DIVIDED CIRCLE, for the determination of indices of 
refraction from the angle at which light is polarized, and 
other special methods. 
16. One of two large SPECTROMETERS, with certain peculiarities 
specially adapting them to general spectrometric work. Made 
by J. Grunow. 
17. D’ARSONVAL GALVANOMETER. In these galvanometers 
the permanent magnet is stationary, and the coil swings and 
is rotated by the current. 
18. New form of DIFFERENTIAL GALVANOMETER, with remov- 
able coils and bell magnet. Made by J. Grunow. 
