SCIENCE-GOSSIP. 



astronomer's attention having been thus specially 

 drawn to the object, he has a ready test for the 

 correctness of his supposition that he has indeed dis- 

 covered a planet. He subjects the interesting little 

 globe to a closer examination, and he watches its 

 position carefully with regard to the adjacent stars. 

 An hour is often sufficient to dispel all doubt. In that 

 time the little body will have moved quite far enough 

 to render its planetary nature unmistakable. The 

 astronomer's toils are rewarded. His labour in 

 making the map, and his assiduous comparisons of 

 it with the sky have received their recompense, 

 and astronomy is enriched by the addition of a new 

 planet to those already known. When the newly- 

 discovered member of our system has been carefully 

 observed three times, and has had its place ac- 

 curately determined on the heavens, then all is 

 done. The mathematician takes its further wan- 

 derings under his care, and wherever the little body 

 may go, the calculator still retains it under the 

 surveillance of his figures. He can at any moment 

 tell the precise spot which it occupies on the 

 heavens. 



These little worlds will generally be found rather 

 disappointing objects as telescope spectacles. They 

 are both too small and too far off to make effective 

 pictures. But we have been able to learn some- 

 thing about them in spite of all the difficulties, and 

 the more interesting facts I shall here mention. 

 First as to their size. In this respect they vary a 

 good deal ; but a general notion of their dimensions 

 may be thus obtained : imagine a globe as big as 

 our earth to be portioned out into a million equal 

 parts. Suppose that one of these parts was 

 rounded into a ball ; it would be about eighty 

 miles in diameter, and would be large enough 

 to make a world about the medium size of one 

 of the class of planets now under consideration. 

 Some of the little worlds already known to us would, 

 indeed, be hardly one-thousandth part as large as 

 the globe, whose formation I have just described. 

 The houses and buildings of London or Birming- 

 ham would be sufficiently extensive to cover one of 

 these little globes completely. From various in- 

 dications we have good reasons for believing that 

 the material elements out of which these little 

 worlds are constituted are not dissimilar from 

 those we know so well on the earth. For example, 

 I should think it almost certain that the little 

 worlds could be found to contain iron ; I should 

 also expect that pieces of stone chipped from one 

 of these small planets would in many cases have 

 considerable resemblance to rocks that are to be 

 met with here. I may certainly say that there is 



no reason for us to think that the other planets 

 contain any elementary substance different from 

 those we know on the earth. 



It seems not at all unlikely that certain of these 

 little worlds may offer an abode to properly con- 

 stituted living beings. At a first glance it might be 

 conjectured that the stature of the inhabitants 

 ought to bear some proportion to the size of the 

 globe on which they dwell. For little worlds, 

 Lilliputians would seem to be suited ; while for 

 vast worlds, Brobdingnagians might appear as 

 appropriate tenants. But if we look a little more 

 closely into the matter, it will appear that this 

 notion that the bigger the globe the bigger the 

 inhabitants is quite erroneous. The little people 

 might be able to do pretty well on either a large globe 

 or a small one, but for the very big people the small 

 globe would certainly be better than a large one. 

 How is this you may well say ? I shall endeavour to 

 make it clear by an illustration. Let us suppose a 

 tiny mannikin, three inches high, and a giant twenty 

 feet high, both of whom are, however, to be propor- 

 tioned in every part of their bodies just as a man 

 of ordinary stature. We may inquire how far the 

 man, the mannikin, and the giant would each be 

 adapted for a residence on globes of the different 

 dimensions. The smallest of them I take to be a 

 little world a few miles in diameter, our own 

 earth will serve as a globe of medium dimensions, 

 while Jupiter is the illustration of a truly great 

 globe. On the little globe the mannikin, the 

 man and the giant could all stand and walk or 

 run about merrily. On the earth the mannikin 

 would be as sprightly as possible, but the giant 

 would hardly ever be able to stand ; his weight 

 would be too great for his muscles. On Jupiter the 

 man would find himself almost as impotent as the 

 giant, while the mannikin would still be able to 

 retain and enjoy his freedom. The little globe, 

 therefore, is the only one of the three which would 

 suit the giant. But I certainly am not going to add 

 that I have any reason to think that there are giants 

 dwelling on the little planets. 



Suppose, however, we were able to land on one 

 of these minor worlds, the smallness of the mass 

 beneath our feet would produce a marvellous 

 transformation in the freedom of our movements, 

 our bodies would seem so light and buoyant that we 

 could easily jump over a house, and if we fixed wings 

 on our arms we could fly like a bird or a bat. This 

 would be possible, because the weight of our bodies, 

 which would have to be raised for flight, would seem 

 so much less than it does here, even though its actual 

 material character was unaltered. A fall from a 



