MR. SEVERN’S LECTURE.

New Zealand Times, Volume XXXII, Issue 4980, 9 March 1877, Page 5

MR. SEVERN’S LECTURE.

Those who attended St, George’s Hall last evening were treated to a lecture more interesting than usual. Mr. Severn, whose scientific, knowledge is very extensive, has for years been engaged in the collection of scientific apparatus, and is therefore in a position to illustrate his discourse effectively, and to eon-, vey information and entertainment at the same time. The attendance last night was large, and those present appeared highly delighted with the lecture and accompanying experiments. The subject was “ The Sun and Modem Solar Discoveries.” In the centre of the hall was placed Browning’s largest lantern for scientific purposes. This instrument is illuminated by means of a clockwork mixedlime jet, and we understand it gives a steady light for several hours, and one of the first class. The varied aspects of the sun ■ were brought under review ; then Mr. Severn explained that astronomers had for a long series of years been watching the surface of the sun. A view was thrown on the screen which simply represented a white disc, or the sun as viewed

by the naked eye. The audience were now supposed to be transported to an observatory, and here they were shown the spots arid the movements of. the solar spots across the disc of the sun. It was thus proved that the sun rotated on his axis in about 25J days ; also that the spots seen On his surface only appeared ln certain regions pf the surface—these were called the spot zones. A photograph by Mr. Browning, of London, taken by means of a 12J silvered mirror, was next exhibited. It was explained that now and again these spots could be seen by the unassisted eye, but of course protected by smoked glass. At other times the telescope was required to make them out. This photograph clearly rendered visible not only the various spots then visible, but the penumbra and mottled appearance of the general surface. A magnificent picture of a large solar spot was now shown. Here all the grand details almost indescribable were clearly seen. Mr. Severn explained that this spot was in size many times larger than the earth. The portion termed the “ willow leaves” was next explained, and each of these apparently small bright markings was said to be equal in dimension to the whole of New Zealand. A beautiful diagram or table showing the results of Schwabe’s . .(the Danish astronomer) work—extending, over 37 years—was moat instructive, and showed that the solar spots reached their maximum numbers every eleven years. Very fine photographs, showing the sun totally obscured by the moon, taken by Major Tennant in India, were next shown on the screen.. Here new phenomena were brought to view, viz., the prominences ot erruptions, and the glory oflight shining out into space. Many millions of miles \yere clearly visible to every one in the hall ; then followed derail views of the solar outbursts, some rising to 150,000 miles, and changing their forms very quickly, indicating very violent disturbances in ; the solar atmosphere. The scientific portion of the lecture on the sun was brought to a conclusion by a fine chemical experiment representing a solar eruption ; bn tie screen it appeared almost as real, the jet of red matter seemed to bevomited upwards exactly as it was described. The audience were most attentive throughout, and seemed intensely gratified with the discourse, which was given in a plain, straightforward manner, and without any notes. The decomposition of water was next illustrated on the screen, and this method is a vast improvement on the old plan—the whole screen was, in fact, a slide holding water; at the top were the platinum wire poles, and the moment the galvanic battery was connected the action began. From one pole issued forth hydrogen gas, from the other oxygen, these being the constituents of water. It was most instructive to watch the number and rapidity of the hydrogen bubbles as compared to oxygen, and when the battery was reversed the action was instantly changed. A number ,of very fine photographs of Paris, Pompeii, the Pyramids, and other subjects, were now shown, as .also some exquisite photography of statuary, and instantaneous photographs of some of the animals in the Zoological Gardens, London. These were simple, perfect, and of course lifelike.' The beautiful experiment of the growth of crystals growing in a solution’ of lead was made, the latter being decomposed by means of galvanism. This was a moat beantiful and well-executed piece of manipulaticn, as indeed were all the experiments. Some microscopic objects were shown, the kaleidoscope, and the radiometer, quite lately .invented by Mr. Crookes, and which was proved to rotate’ in some mysterious manner by light bn ,the force of light. A number of persons remain to get a closer glimpse of the wonderful instrument. Tlhe next lecture is on Saturday, wh,en' light and spectrum analysis will be explained; :&c.