Introductory course of natural philosophy for the use of schools and academies. Ed. from Ganot's popular physics. By William G. Peck (1869)
Ganot, Adolphe, 1804-1887, Peck, William Guy, 1820-1892 · New York A.S. Barnes · leaf 372
io does the declination vary in iha United Stalest What is the diurnalvariation ? The annual variation ? COMPASSES. 369 Irregular changes are called perturbations. They usually takeplace during thunder storms, during the appearance of the auroraborealis, and in general, when there is any sudden… … Fig. 243. Fig. 243 represents a compass. It consists of a compass-box, having a pivot at its centre, on which is poised a delicatemagnetic needle. Around the rim of the box is a graduatedcircle, whose diameter is somewhat less than the length ofthe needle, and of which the pin is the centre. The…
Physics
Internet Archive · Gerstein Library, University of Toronto · Public Domain Mark 1.0. Free to use for anything.
