Intelligence and Miscellaneous Articles. 283 



height of the liquid in the tubes is changed during the equalization 

 into vis viva of the liquid. This may again be transformed into 

 energy of the original kind, so that the fresh difference in height 

 has the opposite position to the former. In the convertibility of 

 the two energies into each other is found the reason of the vibra- 

 tory motion which would otherwise be conceived to be due to 

 inertia. If, owing to friction, part of the energy is transformed 

 into heat, which is not convertible, the amplitudes of the vibrations 

 are continually slower. The motion is as if the liquid had not 

 complete inertia. 



To the difference of potentials between the plates of a charged 

 condenser an electrical energy corresponds. If the plates are 

 connected by a wire, part of this energy is converted into heat, 

 owing to resistance ; the rest is again changed into another energy, 

 which, as the fact of the oscillating discharge shows, may again be 

 transformed into an electrostatic one, in such a manner that a dif- 

 ference of potential is established in the condenser opposite to the 

 original one. The question is, of what value is this energy? In 

 the special case in which the discharging wire is passed spirally 

 round an iron core, the nature of the greatest part of this energy is 

 known. It is the magnetic energy which is accumulated in the 

 magnetized iron during the equalization of the discharge, and 

 which after the equalization is complete still maintains a current 

 in the same direction, and charges the condenser afresh, but in the 

 opposite direction. It is simplest, even in case there is no mag- 

 netic core, to conceive this energy as a magnetic one which has its 

 seat in the magnetization of the medium in which the discharge 

 takes place. This assumption is sufficient also for establishing the 

 laws of electrodynamic induction. — Wiener JSitzmigsberichte, June 12, 

 1890. 



CALORIMETRICAL OBSERVATIONS ON THE DISENGAGEMENT OF 

 HEAT AND LIGHT IN ELECTRICAL DISCHARGES. BY G. STAUB. 



The author determines the ratio N of the total energy E emitted 

 by a gas to that which is perceived as light L. With this view he 

 introduces a Geissler's tube into an ice-calorimeter from the bottom 

 of which the mercury is removed. The ice and water transmit all 

 the rays of light and only absorb those of heat; he then blackens 

 the Geissler tube, and thus retains the visible rays also in the ice- 

 calorimeter. If the quantity of heat in the first case is Q and in 

 the second E, L=E— Q. 



The width of the Geissler tube was altered as well as the pres- 

 sure in it, and condensers and also breaks were interposed in the 

 circuit. The results of the experiment were as follows. 



With the help of electrical discharges in Geissler tubes, light of 

 considerably greater useful effect may be obtained than in the glow- 

 lamp. The maximum for one of Blattner's was 10 per cent., and 

 for a Geissler tube with condensers 32*8 per cent. The useful 



