376 



NATURE 



{Sept. 5, 1872 



principal objects — the foundation of a school of painting. 

 Already we have seen in Melbourne copies after pictures 

 in our national collection of no small merit, and giving 

 good promises of future excellence. For so young a 

 colony as ours the number of students is even now large, 

 and is, I hear, increasing. The National Museum at the 

 University, under the care of Prof M'Coy, is becoming 

 more complete and perfect every year ; the space that has 

 become available, through the removal of many of the 

 mining and machinery models to the Technological Mu- 

 seum will be most advantageously bestowed upon nume- 

 rous beautiful specimens and collections which hitherto 

 have appeared somewhat too crowded. Botanical science 

 in the colony, represented by our fellow member, Baron 

 von Mueller, has made considerable progress during the 

 past year. I have already referred to his lectures on 

 forest culture, in which he clearly set forth the more im- 

 portant and lasting objects of a botanical department in a 

 new country, and, to quote his own words, ' A botanic 

 garden has not merely to gratify the passing hour, but 

 has to fulfil great objects of the whole community, as well 

 for this as for the coming generation.' Baron von Mueller, 

 I am glad to say, intends shortly to issue some popular 

 works on Australian botany ; the first, I believe, is to be 

 devoted to the ferns, and it is intended to illustrate it by 

 photo-lithography. I have been also informed that Count 

 Castelneau, the well-known zoologist, has prepared a 

 descriptive essay on the fishes of Victoria, which 

 is to be issued with the report of the Acclimatisa- 

 tion Society. I refer to these points, although they do 

 not belong to our past year's history, because they 

 indicate scientific vitality and progress ; and although 

 the fruition may belong to another year of this 

 Society, the work evidently belongs to this. In our 

 Observatory one of the most interesting results of the 

 past year's work is the establishment of the fact that the 

 nebula in r; Argus has not only undergone marked 

 change since the time it was observed and drawn by the 

 late Sir John Herschel at the Cape of Good Hope, but has 

 also exhibited notable change since the erection of the 

 great telescope in Melbourne. Drawings of it made at 

 intervals of only a few months, as was pointed out by Mr. 

 Macgeorge in the paper he read before you at our October 

 meeting, present such differences that we can now hardly 

 escape from the impression that observable ch.anges in 

 this nebula take place very rapidly. Several observers in 

 the southern hemisphere have devoted a good deal of 

 attention and observation to this celestial object — notably, 

 Mr. F. Abbott, of Hobart Town ; Mr. H. C. Russell, 

 director of the Sydney Observatory ; Mr. Tebbutt, of 

 Windsor, New South Wales ; and Lieut. Herschel, in 

 India. Mr. Abbott, I believe, was the fir£t to draw atten- 

 tion to the fact that it no longer appeared as drawn by 

 Sir John Herschel. I\Ir. Russell made a very careful 

 drawing of the nebula as seen with the Sydney 7|-in. re- 

 fractor. Mr. Abbott also made some drawings from 

 observations from a 4.!-in. refractor, and Lieut. Herschel 

 by the aid of a 12-in. reflector. They have all indicated 

 that the general appearance of the ncbulx differed con- 

 siderably from that represented by Sir John Herschel's 

 drawings, although none of the apertures used could in 

 any way pretend to reach the more minute details grasped 

 by Herschel's 2-ft. reflector. Several of the drawings 

 which reached home had evidently not been executed 

 with that precision which is so necessary to establish a 

 fact of this kind in the minds of astronomers who are un- 

 able to see for themselves. There has arisen, therefore, 

 in the minds of many of our most renowned observers in 

 England and elsewhere, doubts as to the real existence of 

 these changes. For it must be remembered that the im- 

 mense distance of the nebulx from us— probably far 

 beyond the most distant stars — makes it necessary that 

 changes such as these described, to be visible to us even 

 with the aid of such light-gathering apertures and optical 



power as is possessed by our large telescope, must be 

 stupendous in the highest degree, and almost beyond 

 comparison with the most ordinary cosmical changes with 

 which we are familiar. Now, since the great telescope 

 has been erected, special attention has been given to this 

 object. Mr. Le Sueur devoted a great deal of time, ex- 

 tending over long periods, to examination and drawings, 

 repeating his observations again after the lapse of many 

 months. He constantly referred to me to establish or 

 throw doubt on his observations, so that I often observed 

 with an unbiassed eye for this purpose. The stars down 

 to the 1 6th magnitude were carefully plotted (those to the 

 1 2th magnitude with the micrometer), to form an un- 

 changing groundwork for the mapping. He announced 

 on several occasions in this society and elsewhere that 

 there were unmistakable changes since Sir John Her- 

 schel's drawings. Mr. Macgeorge, who succeeded 

 Mr. Le Sueur, and who has also observed and drawn the 

 nebula; constantly, pointed out to you in his paper in 

 October last the progressive changes that had been noted. 

 The diagram he then exliibited I had photographed and 

 sent home to Dr. Robinson (one of the Great Tekscope 

 Committee), with a copy of Mr. Macgeorge's paper. The 

 paper got home first, and Dr. Robinson says, in a letter I 

 received last mail : ' I lose no time in forwarding the 

 paper to Sir E. Sabine, Mr. Lassell, and Mr. Warren 



De La Rue Mr. Lassell seems to 



cling to the idea which he published some time ago, 

 that there was no change whatever in j; Argus. He 

 justifies this suspense of opinion by not being able to 

 refer to the drawings, a difficulty which I hope you will 

 soon be able to remove. I think his real difficulty is an 

 opinion that nebula; must be at a distance much greater 

 than that even of small stars, and hence an incapability 

 of conceiving the possibility of such changes as could be 

 visible to us.' The photographs reached him by next 

 mail, and he then writes : — ' The photographs are very 

 remarkable, and I think it is impossible to look at them 

 and doubt the reality of the immense changes that have 

 taken place. Are these changes periodical .' I send one 

 of the photographs by this post to Sir Edward Sabine, 

 with recjuest to forward it to Messrs. Lassell and De La 

 Rue.' It is to be regretted that the minute and careful 

 drawings made by Messrs. Le Sueur and Macgeorge have 

 not yet been engraved, as they establish the facts beyond 

 all doubt, as the photographs sent home were from a 

 somewhat rough diagram intended only to show the prin- 

 cipal features of the observed changes. No one accus- 

 tomed to observing could fail to be convinced of change 

 going on, if he only saw the nebul;"B with a power of six or 

 seven hundred on the great telescope on good nights at 

 at intei"vals of three or four months. Mr. Macgeorge 

 reports from observations made only two months since 

 that still furtlier changes were evident. The full signifi- 

 cance of these changes can hardly yet be estimated ; but 

 they overthrow many of our hitherto-received notions of 

 the condition of these tenants of space. It is a subject 

 of the highest interest in physical astronomy, and one 

 that will demand unremitting observation and drawing 

 for its further elucidation. I am glad to inform you that 

 the Government has given me authority to publish every 

 month the results of our observations in meteorology, 

 terrestrial magnetism, and of other phenomena ; the 

 numbers from the commencement of the year till the end 

 of May are .already before the public. By this means all 

 the useful information derivable from the Observatory 

 work in these branches of investigation is made quickly 

 and generally available. Photography of celestial objects 

 has been commenced with the great telescope, and some 

 exceedingly fine and promising negatives of the moon were 

 taken, enlargements froin which have already been ex- 

 hibited at one of our meetings. Since April the weather 

 has been too unfavourable to proceed with this work. 

 Attempts to obtain photographs of planets and nebukc 



