PHYSICS. 385 



different kinds of absorbing molecules, which, according to the current 

 chemical theory as to the conditions of these phthaleins in dilute 

 alkaline solution, are molecules of two distinct substances. 



Mr. W. G. Mallory has in progress a study of the selective radia- 

 tion of certain oxides of the rare earths. The phenomenon has been 

 known since the time of Robert Bunsen, but its precise relation to 

 ordinary temperature radiation on the one hand and to luminosity 

 on the other has not been precisely determined. A connection with 

 luminosity is strongly suggested by the fact that the emission bands 

 are reversals of the absorption bands of the substance, as in the case 

 of the ruby, and are also identical or nearly so with the emission 

 bands of the oxide under the kathode discharge. 



Dr. C. C. Bid well is investigating the thermal conductivities at 

 high temperatures of certain metallic oxides, employing a modifica- 

 tion of the method of Lees. This will be an interesting extension of 

 his recent work^ on the electric resistance, thermo-electric power, 

 and Hall effect of these oxides. He has also carried his observations 

 on the resistance and thermo-electric power of Fe203 to the melting- 

 point (1390° C.) and finds a reversible transformation point at 1240°. 



Dr. R. W. King is applying an ingenious method,^ recently developed 

 by him, to the measurement of the thermal conductivity of various 

 metals at high temperatures and has in progress a study of the Hall 

 effect in thin films. 



Mr. C. C. Murdock is making satisfactory progress in a study of 

 the behavior of certain photoactive cells with fluorescent electrolytes. 

 This investigation is to be regarded as a continuation of the work of Dr. 

 Percy Hodge^ and Dr. G. E. Thompson^ on the same subject, though 

 it deals with an entirely different aspect of the general problem. 



Nipher, Francis E., Washington University, St. Louis, Missouri. Gravita- 

 tion and electrical action. (For previous report see Year Book No. 14.) 



The following results have been obtained : 



1. Discharge from large condenser through lead wires clamped in a 

 grounded line : Positive discharge, wires become explosive and go up in 

 a cloud. Same potential negative, wires fuse and fall in hot globules 

 on paper below, burning it — scorching it. 



PV 



2. The Boyle-Gay-Lussac constant -jr varies somewhat with 



electrical conditions of the gas. It is a minimum when the potential 

 is zero absolute. 



3. Electrification of a mass of matter decreases the gravitational 

 attraction of that mass for a suspended mass within a metal shield. 

 (Cavendish Exp.) 



iBidwell, C. C, Physical Review (2), vm (1916). 

 ^King, R. W., Physical Review (2), vi, p. 437 (1915). 

 ^Hodge, Percy, Physical Review, 28, p. 25 (1909). 

 ^Thompson, G. E., Physical Review (2), V, p. 43 (1915). 



