CHAPTER XV.
287. What is the origin of the term electricity? What is said of attraction and repulsion in electricity?
288. What is the supposed explanation of electrical repulsion? Explain the difference between resinous and vitreous electricity. What is said of the two supposed electrical fluids? Detail the illustrations of attraction which are stated.
289. State the theory of Franklin. Explain the use of the terms positive and negative. Illustrate the fact that the kind of electricity excited depends on what a substance is rubbed with.
290. What is said of the incorrectness of the terms vitreous and resinous? What is said of conductors and non-conductors? Why are non-conductors called insulators?
291. What marked difference is there between heat and electricity? State the experiment represented in Fig. 258. What is said of electrics and non-electrics?
292. What is said of equilibrium in electricity, and of its disturbance? Give in full what is said of the universality of electricity.
293. State what is said of induction, as illustrated by the experiment represented in Fig. 259.
294. State the experiment represented in Fig. 260. Describe the arrangement and operation of the electrical machine represented in Fig. 261.
295. Describe the cylinder machine. State the experiment with the pith balls. State that with the head of hair.