The Optical Magic Lantern Journal (October 1900)

120 The Optical Magic Lantern Journal and Photographic Enlarger. give two great extensions in the direction of the solar equator, one apparently dividing itself at its outer extremity into two pointed and somewhat curved horns or projections, like the rays of the fish’s tail, while the opposite one appeared single and rather tapering towards a rounded and blunted extremity. In both the coronal streamers seemed to radiate from the | sun’s surface, and, as they extended farther outwards, to be compressed and gathered together to form the great equatorial bundles or extensions described above. These had been observed during the eclipse seen in India in 1898 to extend to a distance east and west of | the sun estimated as being equal to six times the solar diameter. On the present occasion they appeared shorter and less sharply pointed, extending to a distance from two and a half to three diameters from the sun’s centre. Most of the photographs show the planet Mercury distant about two degrees from the sun (and therefore completely concealed by the , brightness of his light, excepting during the ; eclipse), and the streamers of the divided coronal appendage appeared to extend almost as far as the planet’s position. The planet Mars and the brilliant fixed star Sirius were also seen in great splendour by some observers ; while Professor Howe, of Denver University, in | the United States, obtained photographs point of the constellation Aries. The inner parts of the corona, or those situated immediately above the sun’s surface, present many features of extreme interest to astronomers and students of solar physics; but these, being far more luminous than the streamers of the outer | . 'Temperance Teaching by Means portion, require a much shorter exposure, and are best shown in the larger photographs, and in those which received an exposure too short to give any satisfactory image of the outer extensions ; while in those which exhibit the | latter perfectly, the details of the inner portions | and the prominences of the chromosphere are obliterated, as the result of over-exposure. Numerous photographs of the spectra of these portions of the solar envelope have also been secured at the various stations, and it may be confidently hoped that the careful comparison of so many excellent results may tend to throw much light on the constitution of our central sun, and may help materially in the solution of the still unsolved problems in solar physics which engage so large a share of the thought and attention of our leading men of science. Even in England, although only a part of the sun’s disc was obscured, and the brilliant spectacle presented to the observers within the band of totality was denied to us, some | excellent photographs of the partially eclipsed sun were obtained in various parts of the country, amongst others at Hawkhurst in Kent, in Liverpool, and from several positions in the neighbourhood of the metropolis ; while similar success has attended the observers at McGill University in Montreal, and others in various directions. Mr. Evyershed, who had selected a position in the neighbourhood of Algiers, close to the margin of the shadow band, in the hope of securing photographs of the lower portions of the sun’s chromosphere, for which such a position would be especially favourable, had a disappointing experience. A slight error in the accepted estimate of the diameter of the shadow-band led him to select a position. which proved to be about i00 yards outside the desired limit, while the same error led to the duration of the total phase being slightly shorter than had been expected ; the observers at Algiers, in Montreal, and elsewhere, finding their opportunity of observation reduced by two or three precious seconds. Such are the disappointments to which the best laid plans of man are occasionally subject, and such the incidents which, annoying at the time, help to secure the attainment of greater accuracy in showing the minute planet Eros near the first | the future—an object which will doubtless be materially promoted as the result of the many successful observations of this, the last total solar eclipse of the 19th century. of the Optical Lantern. By JUDSON BONNER. A lecture delivered at the World's Temperance Congress London, June, 1900, illustrated with a large numbcr of representative slides, shown vy a powerful electric lantern. \\ HE old as well as the young generally receive more lasting impressions from what they see than from what they hear. Hence it is most important in the teaching of tem) perance principles to attract the eye as well as the ear. The simplest object 4 may help to enforce a truth so that it will not be forgotten. The teacher of science, acting on this theory, proves his statements by means of practical experiments, diagrams, and blackboard illustrations.