50 Mr. J. J. Sylvester on a Point of Notation, 



mine ; though when he places the second wire in the fnll flame, 

 the current is in a contrary direction to that which I obtain. 



My experiments prove, I think, distinctly, that there is a vol- 

 taic current, and that of no mean intensity, due to flame and 

 not dependent on thermo-electricity. 



I know of no better theory to account for these results than 

 that which Pouillet applied to the eff'ects on the condenser, viz. 

 that it is the result of combustion ; the platinum at the com- 

 mencement of chemical action, or where the elements are enter- 

 ing into combination, being as the zinc of the voltaic battery ; 

 and that at the termination of combustion, or at the points 

 where the chemical action is completed, being as the platinum 

 of the voltaic combination. 



Although there is a distinct thermo-curreut produced by the 

 contact of two unequally heated bodies with flame, yet when we 

 see, as in the above experiments, a marked current, in a contrary 

 direction to, and overcoming that which is excited by the thermo- 

 curreut in the flame, and also that at the points of junction of 

 the wires without the flame, I see no means of viewing the re- 

 sulting current as a thermo-current. The blowpipe flame, from 

 its detiniteness of direction, brings out most distinctly this cur- 

 rent ; in other flames, from the more confused circulation of the 

 heated and burning particles, the results are less significant; 

 and the various flame-currents counteracting each other, the 

 thermic current obtains a predominance. 



The current from the blowpipe flame, when the platinum in 

 the fidl flame is cooled, is so marked, that I have little doubt, by 

 attaching to a powerful pair of bellovis a tube from which a row 

 of jets proceeds, and alternating pairs of platinum in flames urged 

 by the jets, a flame-battery might be constructed which would 

 produce chemical decomposition and all the usual efi"ects of the 

 voltaic pile. 



IX. Note on a Point of Notation. By J. J. Sylvester, F.R.S.* 



IT frequently becomes important in algebraical investigations, 

 and in the representation of results, to have a means of 

 expressing that the sign + or — is to be affixed to an algebraical 

 expression, according as certain indices 6^, 6^, 63, . ■ • On which 

 occur therein, and which represent the natural numbers from 1 to 

 n in some regular or irregular order, can be derived from the fun- 

 damental arrangement 1, 2, 3, . . . a by an even or by an odd 

 number of interchanges. An example of this occurred in my 



* Communicated by the Author. 



