Elements of physics for use in secondary schools

by S.P. Meads

This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1896 ...and a cover below with the opposite pole. Electrifying, make light images of pith "dance" between the plates. (j) Wind closely around a steel wire a fine insulated copper wire. Pass small disruptive discharges or a steady " current" through the copper wire from one pole of the machine to the other. Has the steel wire assumed any new properties? Will it attract small pieces of Iron? Exp. 175.--Connect a Geissler-s tube (a glass tube containing rarefied air with platinum wire fused through the ends) to the poles of the electrical machine, and vigorously work the machine. A beautiful glow and play of colors appear, better observed if the room be darkened. The Aurora Ilorealis, or Northern Lights, is believed to he caused by the currents of electricity passing through the rarefied air in which the play of colors is seen. If the air be still further exhausted in a Geissler tube, a point is reached beyond whicb the highly rarelied air becomes an insulator as before any exhaustion. Lightning Kods oftener protect buildings by securing a rapid convective discharge from the cloud to the earth or vice versa, than by conducting a disruptive discharge. Among the requirements for good protection are the The rods should be made of iron or copper with flat cross section or of separate wires. Each rod as far as possible should be without joints or with few and carefully made joints. 2. The rods should rise from all the higher portions of the building, as chimneys, etc. The top of the rod should be composed of several pointed projections made or covered with metal which resists oxidation. 3. Each rod should be separately carried into the moist earth, and packed about with finely broken charcoal, or connected with a large metallic plate. Und...

80 pages, Paperback

Published January 1, 2012