Chemistry and Physics. ATT 
convert all the radiations into obscure radiations. One can utilize 
this specific property of selenium in analyzing the heat rays; also 
m a photographic chamber; in the use of the opthalmoscope, and 
generally in the analysis of the radiation of the sun and the stars. 
— Comptes Rendus, No. xvi, 15 October, 1883, pp. 838-840, 
4% 
2. Telluric Oxygen lines—M. Ecororr has shown that the 
lines A and B of the solar spectrum are due to the oxygen’in the 
earth’s atmosphere. He employed a tube twenty meters long 
closed at both ends by glass plates; filled this tube with dry oxy- 
gen under a pressure of fifteen atmospheres; observed the light 
from an oxy-hydrogen flame and found that the lines due’to the 
absorption of the oxygen were identical with A and B in the solar 
Spectrum. The theory that these lines are due to a cosmical hy- 
drocarbon gas diffused through space is controverted by the ex- 
periments of M. Egoroff, who found that several kinds of hydro- 
carbon gas gave no bands or lines of the character of A and B.— 
Comptes Rendus, 27 August, 1883, pp. 555-557. oe: 
3. A new Capillary Electrometer.—M. A. Curvet has devised 
a modification of Lippmann’s Electrometer which can be readily 
constructed and which will show a difference of potential from 
a volt. Two flasks with lateral orifices on the 
ence of potential can be intercalated between the ends of P and 
The heights of the mereury and water in the flasks A and B 
are such that P and N being connected by a metal wire, the sur- 
faces of separation of the two liquids is in the region of the eap- 
illary portion of the larger end of the thermometer tube. Let a be 
the angle of the cone which is tangent to the surface of the tube at 
the point where the meniscus is formed; a is small angle. 
Let a be the capillary depression and r the radius of the tube. 
Then ¢@=— where M is dependent upon the difference of poten- 
tial intercalated between P and N. The movement of the menis- 
cus is observed with an eye piece. By means of a manometer at- 
tachment differences of potential can be compared by the method 
of Lippmann.— Comptes Rendus pp. 669-672, 17 September, 1883. 
a. ¢. 
4. Haill?s Phenomenon.—M. Aug. Righi modifies the form of 
thin plate used by Dr. Hall; instead of a cruciform plate it has 
any shape whatsoever and carries three electrodes. The current 
