8 Trans. Acad. Sci. of St. Louis. 
disturbed by the movement of near-by objects. Atten- 
tion was called to this phenomenon and to the ‘‘ball- 
lightning’’ discharge in my paper before the Interna- 
tional Congress of Arts and Science in 1904.5 These phe- 
nomena indicate that the negative current is the agent 
which seems to be concerned in electrical action. On the 
negative side of the machine, negative discharge to the 
ground is accompanied with leakage from the machine 
terminals and line to the surrounding air. On the posi- 
tive side a negative flow from the ground to the machine 
seems to be accompanied with an inflow or leakage of 
negative electricity from the surrounding air to the posi- 
tive terminals and line. There is nothing to make neces- 
sary the assumption that any positive discharge is taking 
place through the conducting wires in any of the experi- 
ments here described. The positive ions which appear 
in the gases of the Geissler and Crookes tubes are gaseous 
atoms from which negative electrical particles have been 
separated, by reason of a forced circulation of these neg- 
ative particles through the entire circuit. 
In order to examine more directly the nature of the 
discharge from or towards separately grounded lines of 
the influence machine the method here to be described 
was employed. One terminal of the machine was con- 
nected with an earth connection (G,, Fig. 1) in the yard 
outside of the building, a spark gap of one or two centi- 
meters being made at the machine terminal. The dis- 
charge from the other terminal across a spark-gap of 
about 30 cm., was led to an independent ground (G,) on 
an adjoining side of the building. The conductors in both 
lines were No. 8 copper wires. The line having the long 
spark discharge through it contained a high resistance 
R, near its ground end. This resistance was composed 
of three or four strips of porous cloth bandage, placed in 
parallel, their ends being placed in tumblers of salt 
water. This resistance could be varied by changing the 
5 Present Problems. Vol. IV, pp. 92-101 of the Proceedings. 
