12 Prof. E. Edlund's Researches on the Passage 



resistance of the air, and m the resistance of the rest of the 

 closed circuit, the deflections must, according to what pre- 



cedes, be proportional to 



E— e— r^ 



m 

 If we exclude the rarefied-air space from the circuit, the 



E 



intensity of the current will be expressed by — . This inten- 

 sity, which was measured several times between the obser- 

 vations of series 2, remained (with insignificant variations) 

 constant the whole time. The deflection was too great to be 

 measured by the magnetometer without placing before the 

 latter a bridge to produce a division of the current. It was 

 found by calculation that, without the employment of the 

 bridge, the deflection would have been 1300 scale-divisions. 

 If we subtract from this number the deflections observed in 



series 2, the remainders will be proportional to -• 



3 thus get: — 





Pressure of 



e-KjZ 



the air. 



m 



89-8 . . . 



. . 1274*2 



79-6 • . . 



. . 1272-0 



65-7 • . . 



. . 1270-4 



58'6 • . . 



. . 1207-0 



39-0 • . . 



. . 1201-2 



81-1 * . . 



. . 1258-3 



18-9 • . . 



. . L265-0 



8-2 • . . 



. . 1270-0 



2-9 • . . 



. . 1280-9 



0-58 • . . 



. . 12840 



0-12 . . . 



. . 1300 



* The deflections obtained at different pressures may be regarded as 

 proceeding from the united action of two different currents, namely: — 

 ( I ) fche current which would he produced by the induction-apparatus in 

 I, lie. case in which the rarefied-air space possessed no electromotive force, 

 but merely opposed a resistance to the propagation of the current; as this 

 rei istance diminishes as the rarefaction increases, the current in question 

 would gradually increasewith the latter; (2) the disjunction-current due 

 bo the passage of the Pormer through the rarefied air, and going in a direc- 

 tion opposite to .this. If the disjunction-current he subtracted from the 

 current before mentioned, the resultant will arrive at its maximum at the 

 pressure at which the latter current will have its minimum, Now the 

 observations furnished by experiments 1 and 2 show that in the former 

 the minimum is found at nearly the same pressure as the maximum in the 

 in the latter. Eence we may conclude from this that when in experi- 

 ment 2 the induction-apparatus was employed in the formation of the 

 current, there was also produced in the rarefied-air space a disjunction- 



