Feb. 10, 1888.] 



SCIENTIFIC NE^A^S. 



139 



Young plants of the tree, three or four years old, grown 

 in the Society's conservatory, were exhibited at the 

 meeting. 



LONDON INSTITUTION. 

 The Astronomer Royal for Ireland gave a lecture on the 

 and of January upon the wonders of the visible stars, 

 and the facts and truths we know of them. The visible 

 stars we all know, but there are myriads of others whose 

 light is too faint to touch the human retina, but has 

 power enough to stamp its strange message upon a 

 sensitised photographic plate placed in the telescope. 

 With the aid of many lantern slides the lecturer ex- 

 plained the constellation Leo, warning his audience that 

 no telescope, however powerful, would show the mane, 

 claws, and tail wherewith the artist usually encircled the 

 stars that compose the group. He then took the Great 

 Bear, and told how the unaided eye could discern three 

 small stars within the square of the constellation, and a 

 good opera-glass would show at least eighty more. Ursa 

 Major being selected as a sort of central terminus in the 

 heavens, all set off in various directions to pay visits to 

 Castor and Pollux, to various beautiful double stars that 

 apparently waltz round each other to the slow time of 

 900 years for a single revolution, and to the " Radiant " 

 of Leonides, right on the ecliptic, from whence spring 

 the vast showers of shooting stars that startle and 

 delight our own little world at recurrent intervals. 

 Many of the nebulae are star clusters ; others, such as 

 the nebulas in Andromeda, and the long beams of light 

 with a central intensity, are but masses of such gases as 

 we are cognisant of on our earth. The central scientific 

 question of the lecture was, how is it possible to measure 

 the distances of so-called fixed stars ? and the audience was 

 told how Bessel observed the motion ot a near star by 

 comparing it with another object, and deduced the dis- 

 tance by noting the relative displacement of the two 

 bodies. The nearest star to us is not, however, visible 

 in London ; it is in a sense the property of our cousins 

 on the other side of the globe ; it is bright and beautiful ; 

 it is known as Alpha Centauri ; its sidereal distance is the 

 shortest we know of; and it amounts to twenty millions 

 of millions of miles. The lecturer guarded himself 

 against being accurate as to feet and inches, but he 

 guaranteed every million. To give an idea of this dis- 

 tance, which is almost unthinkable, he supposed a rail- 

 road constructed from Finsbury Circus to this, the nearest 

 of the stars. He asked what the fare would be, and 

 placed the rate at the low figure of one penny for every 

 hundred miles, that is to say, a rate that would take one 

 from London to Edinburgh for fourpence or fivepence. 

 He then took the sum total of the National Debt, at, say, 

 seven hundred millions, and imagined a traveller going 

 with that sum in sovereigns in 5,000 carts to the book- 

 ing office, that being the number of carts requisite to 

 carry the sum in question. Having told his audience 

 the many thousands of years the booking clerk would 

 take to count the sum, working day and night, he asked 

 if we thought it would be sufficient to pay the fare, and 

 startled them by saying that the conscientious clerk 

 would require just 105 millions sterling before the fare 

 was paid. 



Our sun was but one of the host of stars, and if we were 

 200,000 times as far away from him as we are now, he 

 would shrink up into the insignificance of a small star — 

 a very pigmy among the giants. Indeed, from an 

 astronomer's point of view, we attach vastly more impor- 



tance to our little sun than he intrinsically deserves ; for 

 there are other suns, such as Sirius, for example, that 

 are many times as large. The motion of a star across 

 the plane of the heavens can be observed and noted, but 

 the movement of one coming straight at us, " end on," 

 as it were, no telescope can note, and here it is that the 

 valuable method of Huggins comes in. He noticed the 

 displacement of the hydrogen line in the spectroscope ot 

 certain stars, and proved that it arose from their motion 

 directly towards us. 



In his second lecture on the 9th January, Sir R. Ball 

 devoted himself to the Unseen Universe. He began by 

 referring to the vastness of the universe which was un- 

 seen by the ordinary eye, and even by the most powerful 

 telescope which had yet been made. The photographic 

 art was the instrument which yielded to the astronomer 

 a knowledge of innumerable stars which the telescope 

 itself did not reveal. The faintest stars eluded the 

 greatest telescope, but they did not elude the photographic 

 plate, and were impressed in millions upon it where the 

 telescope disclosed no sign of their presence. He ex- 

 hibited several photographic sections of infinitesimally 

 small portions of the heavens, each of which showed an 

 innumerable multitude of stars, most of them, he remarked, 

 quite invisible under the most powerful telescope. It 

 was by the means of photography that the heavens were 

 being mapped with a completeness and on a scale which 

 no telescope could have enabled astronomers to attain. 

 But beside these stars, which were beyond the reach of 

 all our means except the photographic plate, there were 

 other suns which might be said to have gone out and 

 expired, and were now speeding, black and invisible, 

 through the depths of space. Such a fate would one day 

 overtake our own sun. The structure of that body was 

 intermediate between a solid and a gas. It was con- 

 stantly shrinking and becoming less and losing its heat, 

 which it was radiating into space. Yesterday the sun 

 was larger than it was to-day, and the day before yester- 

 day it was larger than it was yesterday. So if we 

 carried our minds back and back through long ages ot 

 astronomical time, we would reach a time when the sun 

 was infinitely larger than it is at present, and when it 

 was a vast mass of glowing vapour launched in space. 

 But our sun was only one among many stars, each of 

 which had shrunk down also, like it, from a mass of 

 glowing vapour, and some of which had already ceased 

 to shine at all and had become invisible. 



THE ROYAL SCOTTISH GEOGRAPHICAL 

 SOCIETY (GLASGOW BRANCH). 

 At the meeting on the 19th ult., Mr. A. Silva White, the 

 Secretary, read a paper on the Antarctic region. 



There was, he said, an area of nearly 8,000,000 of 

 square miles within the Antarctic Circle, where the forces 

 of nature combined to raise up a barrier which, " since 

 the world began," had only been broken through at a few 

 isolated spots by the adventurous navigators of modern 

 times. Within this area — or within the parallel of 70 

 deg. south — they had conclusive evidence of the existence 

 of a great mass of glaciated continental land, which, 

 according to Mr. John Murray, must be some 3,500,000 

 square miles in extent, or greater than the area of 

 Australia. Dirik Guerritz, a Dutchman, is reputed to 

 have been the first to penetrate (January 1600) these 

 remote southern regions ; his vessel, which formed part 

 of a squadron under Simon de Cordes, being driven by a 



