=EXPERIMENT 86. To study the effect of electrical discharges upon the human body.=
_Apparatus._ The condenser (Fig. 52), with E S centrally placed so that the apparatus cannot discharge itself; the hairpin discharger, H P D (No. 48); the electrophorus.
=187. Directions.= (A) Charge the condenser (Exp. 83) with 10 good sparks from E C, then touch I T (Fig. 52).
(B) Recharge the condenser with 10 sparks, then touch F B. Discharge it by again touching I T as in (A).
(C) Recharge with 10 sparks; then place your thumb against F B, and quickly swing the first finger of the same hand over to I T, and get a slight shock.
(D) Recharge with as many sparks as you think you can stand.
(E) Instead of using your hand to discharge the condenser, try the bent hairpin. Keeping one end against F B, swing the other end over near I T.
_=188. Shocks; Dischargers.=_ The two conductors being oppositely charged in the condenser (Exp. 85), it is only necessary to place some conductor between them to allow the charges to rush together. Any conductor so used is called a _discharger_. The hand carried the whole current which caused the _shock_. When I T was touched first, the current was obliged to pass through your body, through the floor, and up the table-legs into F B. Always touch the "grounded" conductor first with the discharger, so that you will get a good spark and _not_ a shock.
=EXPERIMENTS 87-88. To show the strong attraction between the opposite electrifications in the condenser.=
_Apparatus._ Flat box, F B (Nos. 40, 41); sheet of glass, G (No. 38); electrophorus (Exp. 68). The two parts of F B are used for the conductors of the condenser (Fig. 54) for the sake of lightness. The bottoms should be next to the glass, which is used for the dielectric on account of its stiffness. The lower tin should rest upon the table. The glass should be perfectly clean and dry (hot).
=189. Directions.= (A) Charge the condenser with 15 or 20 good sparks from E C.
(B) Lift the condenser by one corner of G (Fig. 54), being careful not to discharge it. Explain why the lower conductor follows the glass.
=190. Directions.= (A) Charge and lift the condenser as just explained (Exp. 87). Fig. 54.
(B) With your right hand touch the upper tin alone, then the lower tin alone.