CANTERBURY COLLEGE LECTURES.

Globe, Volume XX, Issue 1405, 16 August 1878, Page 3

CANTERBURY COLLEGE LECTURES.

“ Magnetism.” The first of a series of lectures on electricity and magnetism was given on Wednesday evening in the Lecture Theatre of the College by Professor Bickerton. The lecturer commenced by saying that we Jived in a world of surprises. Not many years ago, Dionysius Lardnor said that he would eat the first steam ship that crossed the Atlantic, but he had not been able to digest that morsel yet. It was but a few years since the mystery of the electric telegraph was discovered, and now the wonders of the telephone excited our astonishment. Again, we now possessed a still more wonderful instrument, a veritable Baron Munchausen’s horn, by which the astounding wonders of that story were brought before us as actual facts. He alluded to the phonograph, and a still more marvellous discovery had been made recently in the microphone, which so powerfully magnified sound that the faintest noise was intensified to a degree almost incredible. The present lecture would treat on magnetism, which presented many curious problems. The lecturer then proceeded to explain the principle of the loadstone, with the theory of its powers of attraction and repulsion, which he illustrated by experiment, breaking the magnet into a number of pieces, and showing how each piece still remained a perfect magnet. The difference of the influence of the magnet on iron and steel was demonstrated, showing how the latter became a permanent magnet, which was only the case with iron in a very minor degree. Iron was magnetic when under the influence of the electro-magnet—but only then; whereas the effect on steel was permanent. Magnetism by induction was next explained, as also the theory of repulsion. Terrestrial magnetism, with the causes of the variation of the magnetic needle, was explained on the theory that the earth acts with a direct influence upon it, attracting and repelling with equal power in the direction of the (lines of force. The causes of the deviation of the compass on 'board ships was next dwelt on, as well as the influence of magnetic storms, which reached their maximum, on an average, once in eleven years. The same phenomenon was observable with regard to the spots on the sun, which also reached their maximum once in the same number of years, and the same thing was noted with regard to the violent Indian cyclones or storms which had their periodical recurrence also once, on an average, in the same space of time. The earth’s magnetic influence was therefore attributed to the sun. Many theories had been advanced to explain meteoric phenomena, and a great many facts yvere known respecting them, but a necessity existed for collecting and arranging these facts, so as to bring them into an intelligible form. No scientific man cared for facts that were not generalised under certain definite principles that connected them together. Theory led to enquiry, and though that enquiry might show the fallacy of the original hypothesis, still the investigation of the subject frequently developed a hundred new things previously unknown. Hypothesis naturally led to enquiry, which was not the less productive of good, even when the hypothesis was proved to bo erroneous. As an illustration of the fertility of a simple hypothesis, there was scarcely a branch of knowledge which had not been furthered to an enormous extent by the theory of the persistence of the fittest. Apart from science, this specially applied to the Darwinian theory of natural selection, the investigation of which had led to an enormous development of knowledge previously unknown. With these remarks Professor Bickerton brought his instructive lecture to a close, pointing out to his hearers that the lecture they had just heard might bo regarded as a purely preliminary one, and to a certain extent disconnected with the remainder of the course, which would bo more specially devoted to electrical science,