284 NIPHER— MATTER IN ITS [April 19. 



determine whether the explosive effects would be the same when 

 the negative discharge was sent through the wire as when the posi- 

 tive terminal was used. In the former case a compression wave is 

 sent through the corpuscular nebula within the wire. The repulsion 

 effects are impressed upon the oil surrounding the wire. In the 

 latter case the nature of the action seems to be essentially different, 

 as has been pointed out above. 



The wire was placed within a glass tube as shown in the adjoin- 

 ing figure. The internal diameter of various samples varied between 

 one and two millimeters. The length of the tube was 10 cm. The 

 ends of the tube w^ere provided with copper leading-in wires fitting 

 more or less closely the bore of the tube and to which the fine wire 

 was attached, as shown in the adjoining figure. The walls of the 

 tube were from one to two millimeters in thickness. The space 

 within the tube around the wire was completely filled with coal-oil, 

 all air being excluded. The ends of the tube and the leading-in 



[;-•:'. ' ' ^':.-^''/:''^^^^^<^>M'>^/^^''f-^^y:^'^^y/''^^ 



Fig. I. 



wires were sealed with sealing wax, which held the leading wires in 

 place and secured these wires and the glass tube to supporting 

 blocks of hard rubber. 



The source of electricity was an influence machine, provided 

 with a condenser consisting of twenty sheets of glass 66 cm. square, 

 each plate having a tin-foil coating 30 cm. square. These plate con- 

 densers were connected in multiple, the tin-foil area being about 20 

 square feet on each side. A pivotally mounted ground contact 

 could be connected to either terminal of the machine. By means of 

 a similar contact rod either terminal could be connected with one 

 of a set of discharge rods, provided with an adjustable spark gap 

 between the knobs. The other discharge rod was connected with 

 the water-pipe system of the building by means of two No. 8 copper 

 wires in multiple. The apparatus shown in the figure was in this 

 ground line. The ground for the machine was in the vard outside 



