MR. SEVERN'S LECTURE.

Hawke's Bay Herald, Volume XX, Issue 3929, 11 June 1877, Page 2

MR. SEVERN'S LECTURE.

Mr Sevbrw gave the first of his lectured in the Protestant Hall on Saturday nightto a well-filled house. He was introduced j' by his Worship the Mayor with a few appropriate observations. In the cotirse of his introductory remarks, the lecturer observed that there was an impression prevalent in some quarters that there was something infra dig in the circumstance of a man who devoted himself to scientific pursuits giving popular lectures. This view, however, was contradicted both by the precept and the practice of the most eminent scientific lneii of the day* He need only quote the remark df Faraday,that a man of indifferent ability cb'uld giv6 scientific lectures which the ordinary public could not understand, but it took an able man to give such lectures as they could understand. We gave already in anticipation a tolerably full epitome of Saturday night's lecture as delivered at New Plymouth, extracted from the Taranahi Herald. We need not therefore follow it point by point. The first experiment shown was that of Foucault's pendulum, which makes the rotation of the earth a fact patent to" the senses. The experiment was not, of course, new to the older part of the* audience, but all scientific experiments, it is hardly too much to say, are new to th>^^ rising generation in Napier. 'Jr The Radiometer, however, which w&anext shown was, probably, something absolutely new to all of us. It has been invented quite recently by Mr Crookes, an eminent investigator in England, who built up upon it a superstructure of theory in regard to the construction of the universe, which, if it had held good, would have entitled his name ' to' rank with that of Kepler and Newton in the annals of scientific progress. The greater portion of it, however, has, unfortunately, had to be pulled down. The Radiometer is a small mill, made so as to be capable of rotating inside a glass bulbfrom which the ah* has been withdrawn^. The force which makes it rotate is the rays of light and heat. Strike a match and hold it up to it, and it at once begins to revolve. With the view of pointing out the care which was required in conducting scientific experiments and the liability to error involved in jumping at hasty conclusions, Mr Severn remarked that he had seen it stated in the Natural Science Review that moonlight, with its accompanying heat — the surface of the moon is 452 Fahr— is not sufficient to cause the mill to rotate. He himself, however, was in a position to contradict this. He found by experiment that . though the moon's rays were, not powerful enough to overcome the inertia of the mill, when once this was overcome by some other light, as that of a match, and it was set going, the moon's rays would keep it going for any length of time. The most attractive part of the lecture was that which followed, which was accompanied with transparencies projected on a screen by means of the lime light. Among other views, the phenomena of an eclipse of the moon were imitated to the life. The earth's circular shadow was shown on the face of her satellite to the confusion of those who — like the gentleman in Christchurch alluded to by Mr. Severn, and like The Rainbow, a periodical much more widely read and believed in than is universally known — assert that she is square and flat. Photographic views of the moon's surface were shown, which, to all intents, transported the audience to an observatory with all the best optical appliances. These were followed by enlarged photographs of Lunar scenery. The Crater Archimedes, with the Lunar Alps to the left, throwing their long black shadows on the surface of the orb, is a truly marvellous spectacle. Copernicus, Wargentin with the extraordinary disc in its neighborhood, and the other craters, were shown in succession, and, we may say, to a highly appreciative audience. With reference to the wonderful canal — as it is to all appearance— cut through the Lunar* Alps near Plato, Mr Severn made a singular remark. He said that it had quite an artificial appearance, and that changes had. been discovered in it of late; the suggestion apparently being that these changes might not impossibly be the work of some sort of intelligent beings. Who can say what is possible and what is impossible 1 If it is so, these beings must have constitutions very different from anything that our mundane experience enables us even to conceive of. The canal is the subject of much astronomical observation at present. The strictly scientific part of the lecture was followed by the exhibition of a variety of miscellaneous photographs shown on the screen. Several of these were very beautiful and striking. The photographs of the beasts in the Zoological Gardens represented them to the life. The youthful Napierites who have never seen a giraffe or a hippopotamus had an opportunity, on Saturday night, and will probably have others, of seeing very close facsimiles of them. We think it is a piece 'of singular good fortune for the young people of the various towns of New Zealand, and, indeed, for many of the older people too, that Mr Severn should have undertaken his lecturing tour ; and we trust that Napier, which has never shown herself behindhand as a patrcii of art and science will do wha%^. is in her power to encourage him. Light and Spectrum Analysis is the subject of Mr. Severn's lecture for this evening. The experimental portion will be of the greatest interest, and as the subject is quite new to us, and the experiments all of the very best kind, we have every reason to hope that even a larger audience than Saturday's will assemble. It is to be hoped that Mr. Severn may be induced to give a further series of lectures, as, we should imagine, he must be prepared^ to do so if called upon.