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SCIENCE. 



[N. S. Vol. II. No. 40. 



not received that verification wliich, in tlie 

 case of Crookes' search for thallium, was 

 afforded by the actual discovery of the new 

 metal." Kamsay has now shown that this 

 gas is present in dense minerals on earth; 

 but we have now also learned from Lock- 

 yer that it and other associated gases are 

 not only found with hydrogen in the solar 

 chromosphere, but that these gases, with 

 hydrogen, form a large percentage of the 

 atmospheric constituents of some of the 

 hottest stars in the heavens. 



The spectroscope has also made us ac- 

 quainted with the motions and even the 

 velocities of those distant orbs which make 

 up the sidereal universe. It has enabled 

 us to determine that manj^ stars, single to 

 the eye, are really double, and many of the 

 conditions of these strange systems have 

 been revealed. The rate at which matter 

 is moving in solar cyclones and winds is 

 now familiar to us. And I may also add 

 that quite recently this wonderful instru- 

 ment has enabled Prof Keeler to verify 

 Clerk Maxwell's theorj^ that the rings of 

 Saturn consist of a marvellous company of 

 separate moons — as it were, a cohort of 

 courtiers revolving round their queen — with 

 velocities proportioned to their distances 

 from the planet. 



If we turn to the sciences which are in- 

 cluded under physics, the progress has been 

 equally marked. In optical science, in 

 1831, the theory of emission as contrasted 

 .with the undulatory theory of light was still 

 underdiscussion. Young, who was the first 

 to explain the phenomena due to the inter- 

 ference of the rays of light as a consequence 

 of the theory of waves, and Fresnel, who 

 showed the intensity of light for any relative 

 position of the interference waves, both had 

 only recently passed awaj'. 



The investigations into the laws which 

 regulate the conduction and radiation of 

 heat, together with the doctrine of latent 

 .. and of specific heat, and the relations of 



vapor to air, had all tended to the concep- 

 tion of a material heat, or caloric, commu- 

 nicated by an actual flow and emission. 

 It was not till 1834 that improved ther- 

 mometrical appliances had enabled Forbes 

 and Melloni to establish the polarisation of 

 heat, and thus to lay the foundation of an 

 undulatory theory for heat similar to that 

 which was in progress of acceptation for 

 light. 



Whewell's report, in 1832, on magnetism 

 and electricity shows that these branches of 

 science were looked upon as cognate, and 

 that the theory of two opposite electric 

 fluids was generally accepted. In magnet- 

 ism the investigations of Hansteen, Gauss 

 and Weber in Europe, and the observations 

 made under the Imperial Academy of Rus- 

 sia over the vast extent of that Empire, had 

 established the existence of magnetic poles, 

 and had shown that magnetic disturbances 

 were simultaneous at all the stations of ob- 

 servation. 



At their third meeting the Association 

 urged the Government to establish magnetic 

 and meteorological observatories in Great 

 Britain and her colonies and dependencies 

 in different parts of the earth, furnished 

 with proper instruments, consti-ucted on 

 uniform principles, and with provisions for 

 continued observations at those places. 



In 1839 the British Association had a 

 large share in inducing the Government to 

 initiate the valuable series of experiments 

 for determining the intensity, the decliua- 

 tiou, the dip and the periodical variations 

 of the magnetic needle which were carried 

 on for several years, at numerous selected 

 stations over the surface of the globe, under 

 the directions of Sabine and Lefro3^ 



In England sj'stematic and regular ob- 

 servations are still made at Greenwich, 

 Kew and Stonyhurst. For some years past 

 similar observations by both absolute and 

 self-recording iustruments have also been 

 made at Falmouth — close to the home of 



