122. Directions. (A) Holding one end of E R in the hand, charge the other end by rubbing it with F C.
(B) With bits of the T P test each end of E R for a charge, and compare the results.
EXPERIMENT 62. To study insulators.
Apparatus. The ebonite sheet, E S (No. 26); flannel cloth, F C (No. 30).
123. Directions. (A) Thoroughly electrify E S ([Exp. 51], D), then lift and hold it in the air, as in [Fig. 28].
(B) By moving your rounded knuckle about near the surface of E S, see if you can get more than one spark from it.
EXPERIMENT 63. To study insulators.
Apparatus. A hard-rubber comb (not furnished); flannel cloth, F C (No. 30); dull pointed nail (No. 19).
124. Directions. (A) Electrify the comb with F C.
(B) Move the nail along near the teeth of the comb, and listen carefully.