44 Prof, von Bezold's Researches on the Electrical Discharge. 



also the circumstance that it was not always unequivocally suc- 

 cessful (for the figures were at times scarcely perceptible) 

 made it desirable to repeat the experiment with another source of 

 electricity. The electrical machine was therefore replaced by 

 the inductorium, one pole being connected with the spark-mi- 

 crometer and the other with the earth. The knobs of the elec- 

 trometer were gradually moved apart. 



As long as the striking-distances were small, figures were 

 formed which were of the same kind as that of the electricity 

 passing across the break ; that is, when the negative pole of the 

 inductorium was connected with the micrometer, negative figures 

 were formed, and vice versa. But as the striking-distance be- 

 came greater, the diameter of these figures diminished. While, 

 for instance, in one series with a striking-distance of 1 millim. 

 negative figures of about 15 millims. diameter appeared, when 

 the striking-distance was 10 millims. this diameter diminished 

 to 2 millims. On continuing to increase the distance between the 

 knobs, the figures ceased for a while, until when the striking- 

 distance was more than 15 millims. they again occurred, and 

 were decidedly positive in character. 



Hence there was here a complete transformation of pheno- 

 mena. While with small striking-distances the path of the cur- 

 rent is that represented in fig. 2 by the dotted arrows, with 

 greater striking-distances another path appears, denoted by the 

 perfect arrows. 



Working with positive electricity, positive figures are first 

 obtained, which, when the distance is increased, continually 

 diminish, then disappear for awhile, and are ultimately replaced 

 by negative ones. The transformation first occurs in this case 

 with greater striking-distances than is the case in working with 

 negative electricity. 



These, as well as many similar differences in the phenomena, 

 according to the kind of electricity used, doubtless owe their 

 origin to the circumstance that equally intense discharges of the 

 two electricities produce figures of entirely different sizes. Hence 

 also it may arise that, so frequently, alternating discharges of a 

 decidedly negative character* produce figures which at first 

 sight might be taken for positive, while the converse never oc- 

 curs. For if we imagine a negative and a positive discharge 

 passed successively to the same position on the plate, the former 

 must far exceed the latter in intensity if it be not concealed by 

 traces of the latter. 



Yet though there are so many minute points to be discussed 



* By an alternating discharge of a positive character I mean one in which 

 the algebraic sum of the quantities of electricity discharged is positive, 

 and vice versa. 



