December i6, 1909] 



NA TURE 



191 



disc, seemed to be "triple." This continued to be an 

 unsolved riddle for nearly fifty years, until Huvtjens, 

 by using much improved telescopes, showed that it was 

 caused by a detached flat ring- round the planet. 



In the meantime, other observers lost no time in 

 taking up the new study of the heavens. Before the 

 end of 1608 Simon Marius, of .Anspach, procured a 

 telescope with which he found the satellites of Jupiter 

 one day later than Galileo did. He continued for some 

 years to follow their motions with great perseverance 

 and skill, and produced valuable tables of them in his 

 " Mundus Jovialis," published in 1614. Unfortunately, 

 he roused the jealousy of Galileo, who accused him 

 of plagiarism, an accusation which, up to a few years 

 ago, most historians of science were inclined to consider 

 proved, but which has now been thoroughly disproved 

 by a detailed study of the observations of Marius by 

 Oudemans and Bosscha. Marius w'as also the first 

 to notice the phases of Mercury and the spurious discs 

 of the fixed stars, which the imperfect telescopes of 

 Galileo had failed to show. Even to the sim was the 

 new instrument directed ; Galileo says he saw the 

 sun-spots irfthe summer of 1610, but he does not 

 seem to have taken any interest in them at first, and 

 did not, as usual, announce the discovery, either 

 openly or through an anagram. Thus Johan Fabricius 

 was the first to publish the discovery of sun-spots early 

 in 161 1, though Galileo made up for his hesitation by 

 systematic observations, and by being the first to 

 recognise that the spots are formations at the surface 

 of the sun itself, and not bodies moving round the 

 sun, as Scheiner, the third and most assiduous 

 observer of sun-spots, for a long time maintained. 



The Dutch or Galilean telescope did not for long 

 remain the only telescope used by astronomers. Al- 

 ready in 1611 Kepler published his "Dioptrice," in 

 which he clearly showed the effect of combining 

 various lenses and the advantages of the "astronomi- 

 cal telescope," in which a real image of the object is 

 formed by the object-glass at the focus of the latter, 

 which is viewed through a magnifying convex eye- 

 lens. A year or two later Scheiner, and following him 

 I'ontana, actually constructed and made use of tele- 

 scopes of this kind, while the inconvenience of the in- 

 verted image produced by them was obviated by the 

 mtroduction of an additional lens in the "terrestrial 

 telescope " to re-invert the image formed by the 

 object-glass. The importance of the real image, which 

 allows a wire or a wire-cross placed at the focus to be 

 seen through the eye-piece as sharply as, and coincid- 

 ing with, the image, was recognised about 1640 by 

 William Gascoigne, who applied a telescope to a 

 quadrant for measuring altitudes, an application which 

 had been suggested in 1634 ^y the French astrologer 

 Morin, who, however, only possessed a Galilean tele- 

 scope. Outside England Gascoigne's idea probably 

 remained unknown, and it was not until 1667 that 

 Auzout and Picard applied telescopes to measuring 

 instruments, and thereb)' immensely increased the 

 accuracy attainable in astronomical observations. 



The importance of the invention of the telescope for 

 the advancement of astronomy is not to be measured 

 only by the insight it gave into the nature of the 

 heavenly bodies, and the aid it rendered in following 

 their movements more accurately. It also rendered 

 an important service by making the Copernican 

 system appear more natural and reasonable in the 

 eyes of every unprejudiced thinker. Hitherto this 

 system had probably to most people appeared to be 

 nothing but a new way of " saving the phenomena " 

 (to use an expression of the ancients), that is, a new 

 method of calculating the motions of the planets, 

 which anyone might use, whether he believed in the 

 reality of the earth's motion or not. Two circum- 

 stances had contributed to give an appearance of un- 

 NO. 2094, '^'OL. 82] 



reality to the new system; first, the numerous epicvcles 

 which Copernicus had been compelled, like the ancients, 

 to use in his planetary theories (because he did not 

 know- the first two of Kepler's laws, and therefore had 

 to confine himself to combinations of circles), and 

 secondly, the spurious preface which, without the 

 knowledge of Copernicus, had been added to his book, 

 in which the system was spoken of as a mere hvpo- 

 thesis which need not be supposed to be true. To 

 assume the earth to be one of the planets was also a 

 difficult thing, so long as absolutely nothing was 

 known about the other planets. As to the moon, the 

 ancients had supposed that it must be a body rather 

 like the earth, and the telescope only confirmed this 

 hypothesis. But adversaries of the Copernican svstem 

 had always asked how the earth could carry the moon 

 along with it during the annual motion' round the 

 sun, or why the moon alone should form an exception 

 to the general rule by moving round a planet instead 

 of round the sun ? Now Galileo could point to the 

 undeniable fact that Jupiter, during its orbital motion, 

 carried four satellites or moons along with it. The 

 discovery of the phases of Venus and Mercurv deprived 

 opponents of Copernicus of another favourite weapon, 

 for they had been wont to proclaim that if Venus 

 moved round the sun it ought to show phases like 

 the moon. Again, the discovery of sun-spots, objects 

 of a temporary nature, supplied a very striking proof 

 that the Aristotelian doctrine of the immutability of 

 all things celestial would have to be given up. While 

 the analogy between the earth and the planets grew 

 stronger every day, it was also of great importance 

 that the fixed stars in the telescope appeared as mere 

 luminous points, so that the apparent diameters of 

 several minutes attributed to them by all previous 

 observers were proved to have no existence. This put 

 an end to the serious objection raised bv Tvcho Brahe, 

 the greatest practical astronomer since Hipparchus, 

 that a star having no annual parallax and yet show- 

 ing a considerable apparent diameter must be incred- 

 ibly large. 



.As it were in a twinkling of an eye, the whole 

 aspect of the universe had been changed by the inven- 

 tion of the telescope. That this was felt in some wav, 

 even by determined enemies of the idea of the earth's 

 motion, may be seen from the statement made bv 

 Clavius, the chronologist, in 161 1, that astronomers 

 would have to look out for a system which would 

 agree with the new discoveries, as the old one would 

 not serve them any longer. The question could no 

 longer be, "Do you believe in the earth's motion?" 

 it could now only be whether the arguments in favour 

 of this motion w'ere becoming so irresistible that the 

 safest thing to do for its opponents would be to 

 proclaim the doctrine to be heretical. This was accord- 

 ingly done little more than seven years after the 

 invention of the telescope. J. L. E. Dreyek. 



THE YUCHI INDIANSA 



ANTHROPOLOGISTS have exaggerated the evo- 

 lutionary gulf between civilised and uncivilised 

 peoples. The more we learn of the latter the narrower 

 does the gulf appear. A remarkable case in point is 

 that of the Yuchis of Oklahoma, recently studied bv 

 Mr. F. G. Speck. 



Here we have a people engaged in agriculture and 

 cattle-raising, like their white neighbours, wearing 

 the same European dress, and hardly distinguishable 

 from them except in language and colour. It is 

 actually the fact " that many negroes and some poor 

 whites as well are eager enough to work for the 



' University of Pennsylvania. Anthropnlogical Publications of the Uni- 

 versity Museum. Vol 1. No. I, "Elhnologyof the Yuchi lndi.ins.' By 

 Frank G. Speck. (Phil.idelphia : University Museum, 1909,) 



