274 



Dr. Harems Electrical Machine, ^c. 



The prime conductor is supported and insulated by means of 

 wooden posts covered by stout bell glasses, so that the summits of 

 the latter are between those of the posts and the inner surfaces of 

 caps attached to the conductor. By these means the glass is sub- 

 jected to pressure, but is liable to no strain. Such a support com- 

 bines the advantages both of wood and glass. At C C, are the col- 

 lectors. R represents a sliding rod, which may be drawn out to 

 such an extent as to be brought in contact with any apparatus pla- 

 ced under it upon the table. In fact, the large rod in which the rod 

 R slides may be slipped up to any elevation through the hole in the 

 brass ball which sustains it. 



Dr. Harems Battery Discharger for deflagrating wires. 



The instrument represented by the preceding figure, is employ- 

 ed by me in lieu of Henley's universal discharger ; being better 

 adapted to my apparatus, and mode of operating. Two brass 

 plates, S S, are secured to the pedestal by a screw bolt N, 

 which passes though a hole made in each, near one extremity : 

 the plates are thus allowed a circular motion about the bolt, so 



