592 Singular Effect of Voltaic Electricity [Oct. 



. Of the 6ame bulk. Of the same weight. 



Gaseous oxide of azote 1*3503 0*8878 



Olefiant gas 1*5530 1*5763 



Carbonic oxide 1*034.0 1*0805* 



{To be continued.) 



Article X. 



Account of a singular Effect of Voltaic Electricity on a slender 

 Platina Wire. By George John Singer, Lecturer on Expe- 

 rimental Philosophy. 



(To Dr. Thomson.) 



SIR, 



During a series of experiments on the effect of various 

 mediums on the ignition of platina by voltaic electricity, a wire 

 of that metal -^-nth of an inch diameter and three inches long 

 was extended in the centre of a globular receiver, which con- 

 tained about 22 cubic inches of hydrogen gas. 



The wire was then placed in the circuit of a voltaic battery 

 of such power as (it had been previously ascertained) would 

 produce a white heat on a similar length when exposed in the 

 open atmosphere. 



On completing the circuit there was not any appearance of 

 ignition, but the wire vibrated strongly, and suddenly exhi- 

 bited a most extraordinary result ; near two inches of its length 

 being split into a bundle of minute fibres, irregularly diverging 

 from a central thicker portion, and continuing attached to the 

 remaining wire at each extremity, so as to assume the form 

 of a lengthened spheroid, corresponding in appearance to an 

 electrified bundle of threads having their ends fastened together. 

 The fibres were so minute as to be scarcely visible to the un- 

 assisted eye, when viewed separately. One of these being 

 compared under a microscope with a fine wire drawn by Dr. 

 Wollaston's process, was found to have a diameter of less than 

 the 5000th part of an inch. 



In the course of innumerable experiments on the fusion of 

 wires by common electricity, I have observed no similar effect ; 



air j because it constitutes *ths of air, and because the specific heat of oxygen 

 differs but little from that of air. 



» To calculate the specific Iieat6 of the same weights of the gases we have 

 employed the specific gravity of olefiant gas given by Saus>sure iu the Ann. de 

 China Ixxviti. .57, aud the specific gravity of the other gases given in the Mem. 

 d'Arcucil, ii. 253. 



