360 Nexo Galvanic Experimerits and Phcenomcna. 



was isrnited at the outer eds,e or fi'inore of the conical fihn of 

 flame. So soon as the communication was made with the 

 conductors, the ignition, as before, shot through the wire and 

 across the cone. In that portion of the wire which was en- 

 cased by the flame, no expansion of vohune appeared. Fusion 

 of the wire supervened. 



■ The phaenomena here exhibited clearly show that the heat 

 of the ambient medium isithin the cone is less intense than 

 that displayed at the edge or superficial envelope of flame. 



Plumbago finely acuminated and attached to one of the 

 conductors was introduced into the cone of flame ; when the 

 contact was completed with the opposite pole, a very brilliant 

 star-Ulce combustion supervened. 



All these phaenomena seem to show that the deflagration of 

 metallic laminte and ignition of wires are perfectly independent 

 of the medium in which such are posited; and also that the 

 heat of common Jlame conjoined with that evolved through the 

 agency of galvanism do produce by their combined agency an 

 aggregate of superior intensity in relation to ignition. 



Part of a steel wire was wrapped round with platinum wire. 

 On completion of the contact, only that part of the steel wire 

 denuded of the platinum conld he ignited, the I'emaining part 

 not being so susceptible. 



This would tend to prove the materialitij of caloric. Two 

 conducting wires instead of one being employed, a channel of 

 double diameter was pi'ovidcd (though by separate canals) 

 for the flux of the calorific matter from pole to pole. 



If the ends of the conductors repose on a narrow magnetized 

 plate of steel, an interposed thread of steel or platinum is in- 

 capable of being ignited. : the directors may be even made to 

 glide along the wii-e until contact is complete ; yet ignition 

 will not follow. So soon, howevei", as either end is elevated 

 from the bar, the wire is ignited and fused. 



If a steel wire be interposed between the directors, and the 

 distance be sufficient, so as to elevate it to a temperature not 

 exceeding a cherry red heat, the wire becomes blued in patches, 



rapid combustion, is as completely extinguished as if plunged into water. 

 Potassium itself carnot by possibility be made to c\\\\hit flame under such 

 circumstances. A beautiful expression of the structure of flame may 

 be obtained by introducing a xlrnw transversely, the outer or exterior sur- 

 face of the flame will char and consume flic portion whicli so protrudes, but 

 the intermcdinle part will remain untouched by the flame ; and over it, the 

 fire has no power. The distinguished chemist in question will readily re- 

 collect his pointing out to mc that gunpowder might be ignited by being 

 let fall througli tlic exterior part of flame ; and when Mr. Pcpys was, last 

 winter, told of my experiments of the nonsiipport of combustion within flame, 

 he expressed surprise it should be so. 



and 



