EXPERIMENTS. 151 



b^ck to the table ; they are attracted and repelled by the 

 electrified inside surface of the glass, the electricity of which 

 they gradually conduct to the table. If a person having long 

 hair, not tied up, be placed upon an insulated stand, and, by 

 means of a chain be connected with the prime conductor, 

 when the machine is put in motion, the hairs on his head, by 

 repelling each other, will stand out in a most surprising man- 

 ner. A piece of sponge, filled with water, and hung to a 

 conductor, when electrified in a dark room, exhibits a most 

 beautiful appearance. If a piece of sealing-wax be fastened 

 to a wire, and the wire be fixed into the end of the conduc- 

 tor, and the wax lighted, the moment the machine is worked, 

 the wax will fly off in the finest threads imaginable. Take 

 a two ounce phial, half full of olive-oil, pass a slender wire 

 through the cork, and let the end of it be so bent as to touch 

 the glass just below the surface of the oil } then place your 

 thumb opposite the point of the wire in the phial, and if, in 

 that position, you take a spark from the charged conductor, 

 the spark, in order to reach your thumb, will actually per- 

 forate the glass. In this way holes may be made all round 

 the phial. 



Questions. — 1. What parts of bodies contain the electric fluid ?- 

 2. When is a body said to be electrified ? 3. What experiment may 

 be made with seahng-wax ? 4. When is a glass tube said to be ex- 

 cited ? 5. What is said respecting an excited tube when in a dark 

 room.'' 0. What are conductors of electricity .'' 7. Electrics, or non- 

 conductors .'' 8. When is a surface positively, and when negatively 

 electrified.'' 9. When is a conductor said to be insulated? 10. What is 

 said of the human body as a conductor .' 11. When do sJurfaces repel, 

 and when attract each other ? IS. What takes place when a conductor 

 receives the electric fluid .'' — non-conductor .'' 13. When is a plate 

 of glass said to be charged .'' 14, What is an electric shock ? 15. 

 Describe the electrical machine. 16. What are some of the experi- 

 ments that may be made with it ? (See Electrical Machine, fig. 49.) 

 [Note. The earliest account of any known electrical effect is by the 

 ancient naturalists, Thales and Theophrastus, who flourished, the fir.st 

 600, and the latter 300 years before the present era.] 



