Intelligence and Miscellaneous Articles, 153 



The question, however, deserves a closer examination ; and this 

 we intend to give it. We will therefore not at present dwell on the 

 consequences which may be deduced from our experiments — in par- 

 ticular as regards the constitution of the luminous gaseous thread 

 which forms the jet, and which has a mechanical force so pronounced. 

 We will merely observe that it has a marked analogy to that part 

 of the electric discharge from the RuhmkorfF coil, in air under the 

 ordinary pressure, which M. Perrot designated by the name aureole, 

 and which he found susceptible of displacement by a simple mechanical 

 impulse such as the breath. — Comptes Bendus de V Acad, des Sciences, 

 April 29, 1872, p. 1141. 



ON THE ELECTRICAL CONDITION OF GAS-FLAMES. 

 BY JOHN TROWBRIDGEj ASSISTANT PROFESSOR OF PHYSICS. 



Prof. H. Buff, of the University of Giessen, published in the 

 Annalen der Chernie imd Pliarmacie, vol. Ixxx. p. 1, and in the Phil. 

 Mag. of Peb. 1852, an investigation of the electrical properties of 

 flames. He reviews at first the different theories in regard to the 

 subject ; Becquerel, for instance, finds electric opposition in all 

 directions in flames, v>^hich depends npon the difference of the tempe- 

 rature of the metals immersed in them. Pouillet recognizes a motion 

 of electricity ovlIj from the interior to the exterior, and hence also 

 from the base to the summit of the flame ; Hankel, however, finds 

 a motion the reverse of this in the flames produced by the ignition 

 of spirits, and states that it is independent of the temperature of the 

 immersed conductor. 



Prof. Buff then gives the following as the results of his investi- 

 gation : — 



1. Gaseous bodies which have been rendered conductible by strong 

 heating are capable of exciting other conductors, solid as well as 

 gaseous, electrically. 



2. When a thermo-electric circuit is formed of air, h3'drogen, or 

 carburetted hydrogen, alcohol vapour, charcoal, or, finally, a metal, 

 whether combustible or incombustible, an electric current is deve- 

 loped, which proceeds througli the air from the hottest place of con- 

 tact to the less warm place. 



3. The development of electricity which has been observed in 

 processes of combustion, and particularly in flames, is due to thermo- 

 electric excitation, and stands in no immediate connexion with the 

 chemical process. 



4. The products of combustion do not by any means, therefore, 

 occupy the relation to the burning body which has been assumed by 

 Pouillet ; if positive electricity rises with the ascending gases, it is 

 only in the degree in which the air exterior to the place of hottest 

 contact is connected by a proper conductor. 



In fact, if we mechanically cause the bell-glass, in which the jet is, to turn 

 on its axis, the jet presents exactly the appearance of the spokes of a wlieel 

 when the rotation attains a certain degree of rapidity. 



