Observations on Electricity. 353 



errors were committed, and on the first trial it made only eighty 

 revolutions a minute. The remodeling was delayed until fur- 

 ther subscription should warrant the proceeding ; and I regret to 

 learn that the recent disastrous fire in Boston has destroyed the 

 machine and batteries. 



Art. IX. — Observations on Electricity ; by Charles G. Page, 

 M. D., Washington, D. C. 



It is somewhat singular that the following fact has so long re- 

 mained in obscurity, especially as the Franklinian theory has de- 

 rived its principal support from the converse of this fact : " If a 

 pith ball be laid in a groove on the table of the universal discharger, 

 and a Leyden jar or battery be discharged in the direction of the 

 groove, the ball will be propelled in the direction of the passage 

 of the fluid, that is, from the positive to the negative." It must 

 have happened, that in every case of repetition of this experiment, 

 the jar was charged in the ordinary way, viz. the interior or in- 

 sulated coating charged with vitreous or positive electricity ; for 

 it will be found that if the insulated coating be charged with 

 negative or resinous electricity, the ball will be propelled contrary 

 to the supposed direction of the flaid, that is, it will move from 

 negative to positive. " If a card be placed upon the table of the 

 universal discharger, and the wires or directors be brought into 

 contact with the card on opposite sides, but at some distance 

 from each other, the perforation made by a discharge between 

 the points, will be found nearer the negative than the positive 

 wire." By reversing the experiment the same error will be found 

 in this statement. If the negative surface be insulated, the per- 

 foration takes place nearest the positive wire. The same correc- 

 tion will apply to the experiment with the flame of a candle be- 

 tween two cups of phosphorus. 



Curious result from the configuration of the electric spark at 

 the positive and negative surfaces. If a tapering jet from which 

 issues a stream of hydrogen gas be applied to a conductor charged 

 positively, the gas will be inflamed nearly every time the spark 

 is drawn ; but if the conductor be charged negatively, the gas 

 will rarely be kindled, frequently requiring six or more applica- 

 tions before it succeeds. 



Vol. XXXVI, No. 2.— April-July, 1839. 45 



