495 
strip (S), which is about 6 mm. in width, is fastened by means of a small 
screw at (F). To this strip the gold leaf is fastened by means of wax 
or shellac. The rod (D) is terminated at its lower end by means of a 
el 
Fie. 4. 
disk (A), which is 8 cm. in diameter. This disk is screwed onto the end 
of (D), and larger or smaller disks may be used, thereby varying the 
capacity of the electroscope. Supported upon a screw (T) which passes 
through the bottom of the ionisation chamber is a disk (B) the same 
