January 2, 1888.] 



♦ KNOWLEDGE ♦ 



59 



tico-ansated ; fifthly and lastly, the spherico-cuspidated," of 

 which many a popular reader in those days might have re- 

 marked — if thei-e had been popular readers then — what 

 Gilbert's devoted lover remarks of the Tupperian senti- 

 ment : — 



" A fool is bent upon a twig, but a wise man fears a bandit," 

 Which I know was very clever, but I couldn't understand it, 



Hevelius meant simply, however — though he expressed 

 himself anything but simply — that t^atnrn looks sometimes 

 like a globe, sometimes like three globes, sometimes like a 

 globe with handles, sometimes like an egg with handles, and 

 sometimes like a globe with projections. Further telescopic 

 research by Huyghens showed that Saturn is surrounded by 

 a flat ring inclined to the plane in which the planet travels. 

 Cassini's larger telescopes showed the ring to be double ; 

 further re.searches disclosed divisions in the outer ring ; then 

 the inner dark ring (semi-transparent, so that the planet's 

 outline can be seen through it) was discovered ; and with 

 each increase of telescopic power fresh discoveries were 

 made, which are going on still, and will doubtless continue 

 to go on for a long time yet to come. 



Only it is to be observed of this case, as of all such cases, 

 that if each astronomer who was put in charge of each new 

 telescope had been unwilling to examine with it the 

 Saturnian ring-system because already some one else had 

 discovered such and such details, all this pleasing progress 

 wotild have been brought to an end. It will presently be 

 seen why I dwell on this rather important consideration. 



There is scarcely an object of telescopic study which has 

 not in some such way rewarded each increase of telescopic 

 power and each fresh inquiiy by keen-sighted and earnest 

 observers. Every planet either shows more of detail, or 

 shows the details of its surfoce more clearly, or shows that 

 details supposed to have been seen have no real existence 

 when increased telescopic power is applied to its examina- 

 tion. The stars not only appear in greater numbers under 

 such increase of power, but single stars are resolved into 

 double, triple, or multiple stars ; minute companions are 

 resolved into sets of attendants ; and movements are detected 

 and measured which with smaller telescopes might have 

 escaped notice, or only been recognised after a much longer 

 time had elapsed. The star clouds or nebulae are seen in 

 greater detail with larger telescopes, and indeed many new 

 nebulas are usually discovered when higher telescopic powers 

 than had before been used are applied to the search for them. 

 The structure of comets is more and more clearly shown as 

 larger telescopes are used in the study of cometic mysteries. 

 And last, to return to our more immediate neighbourhood, 

 the study of the sun and moon has progressed very obviously 

 and decidedlj' as larger telescopes have been applied to the 

 details of the surface of either orb. 



I may take the examination of the sun's surface as illus- 

 trating in a very effective way the advantages to be derived 

 from the use of large telescopes. 



Galileo, Scheiner, and Fabricius could recognise little 

 more than the fact that the sun has spots on his face at 

 times, and that these spots are carried round in such a way 

 as to show that the sun rotates on his axis. Hevelius noted 

 the maculce or mottling, and the faculce or bright streaks. 

 Wilson recognised the changing appearance of the spots, and 

 the evidence that they are depressions. The elder Herschel 

 recognised the coiTugations. Nasmyth called attention to 

 details which he called the willow-leaves, comparing the 

 appearance to that which would be produced if a number of 

 luminous objects of a form somewhat resembling that of the 

 willow leaf were strewn on a somewhat darker ground. 

 Dawes^nd Huggins showed that with better telescopes the 

 appearance of a bright network on a dai-ker background gave 



place to that of a darkei' network on a bright grovmd, and 

 this appearance in turn to that of a number of bright gi-ains 

 strewn more or less inegularly over a surface which, though 

 relatively darker, is in reality intensely bright ; and lastly, 

 Langley has shown, by yet more careful scrutiny, that the.se 

 grains, the so called rice-gi-ains, are irregular in shape ; that 

 they become elongated in the neighbourhood of spots, and 

 that a number of forms akin in variety alike of individual 

 shape and of combination to the cloud-forms — cirrus, 

 cumulus, and nimbus, cirro-stratus, cirro-cumulus, <fec. — 

 seen in our skies can be recognised in the glowing photo- 

 sphere of the sun. Nor can we yet tell how much more of 

 detail, or, therefore, how much more of significance may 

 come to be recognised hereafter in the structure of the 

 great ruling centre of our system. 



But if new telescopes of increased power are to do what 

 they are unquestionably capable of doing, and what asti-o- 

 nomy is entitled to expect of them, there must be no per- 

 functory control of the observatories in which they are 

 erected. There is a danger (which we have recognised in 

 the old country, and which exists, I fear, to some degree in 

 America also) lest the large telescopes should come to be 

 spoken of more for what they are capable of doing than for 

 what they are doing or have done. There is further danger 

 lest smaller telescopes alone should be busUy employed, and 

 this rather to encourage the construction of important 

 observatories, capable of splendid work (provided with large 

 telescopes and also managed by persons capable of di-awing 

 large salaries), than with any gi-eat desire to advance astro- 

 nomical knowledge. 



We have bad in England one or two such marked exam- 

 ples of this sort of thing that (knowing human nature to be 

 everywhere much the same) no true lover of science can 

 fail to feel somewhat anxious lest in America also the same 

 thing might happen. Such men as Mr. Huggins, in England, 

 and Dr. Henry Draper, in America, doubtless enable us to 

 entertain the hope that men like the Newtons and 

 Herschels of past times are still among us, who are capa- 

 ble of working zealously at science for science's own sake.* 

 When on the other hand we find, as we have in England, 

 men skilful as observers making their really clever researches 

 a sort of fulcrum for levering up a well-salaried post, and 

 either when such post has been secured or when all hope of 

 securing it has failed, dropping altogether their zeal for 

 science, we begin to recognise a danger which threatens 

 seriously the future of our big telescopes. 1 mean the risk 

 that they should fall into the hands of men who have no 

 genuine zeal for science, even though in the past they may 

 have done good work in research. Such men there have been 

 even among astronomers, men who have, indeed, regarded 

 large telescopes as instruments by which remarkable dis- 

 coveries might be accomplished, but who have cared for 

 such discoveries only as stepping-stones for themselves. 



* I am quite aware, even as I write these lines, that William 

 Herschel, and in less degree John Herschel, availed themselves of 

 the power that science gives of earning a livelihood, or even of 

 maintaining a family, through some development of scientific 

 research. William Herschel made telescopes for sale, and Jolm 

 Herschel wrote books, from the sale of which considerable sums 

 accrued to himself and to his family. Even if the Herschels had 

 held, as Newton did, salaried posts for work associated with 

 science, it would in no sense have affected the distinction I draw 

 between them and men who value scientific research oiili/ as a 

 means for gaining money. Self-support, and the maintenance of 

 those dependent upon one, are duties which come before even the 

 advancement of science. But we see Newton's zeal for science 

 showing itself in work done independently of all possibility of 

 profit. William Herschel gave up remunerative business that he 

 might devote his whole time to astronomy, on the merest chance 

 that a portion of his scientific work might avail for self-main- 

 tenance. 



