March 1, 1886.] 



KNOWLEDGE ♦ 



141 



now no longer trusted to tlie use of tte same telescope, 

 turned in dift'erent directions, to tell liim (tifter mere 

 counting) the depth of our galaxy of stars in those direc- 

 tions ; he turned different telescopes, gradually increasing 

 the space-penetrating power, in the same direction, to 

 tell hitn, by the power required to resolve the whole 

 field of view into stars, the probable extension of the 

 system in that direction. Herschel made many observa- 

 tions by this method, but in his advanced old age, when 

 these obsei-vations had been gathered together, he did 

 not recognise the absurdity of the result to which thej' 

 tended, on the assumption he had employed. He found 

 regions of the star-sphere, for instance, wherein stars of 

 all orders were richly strewn, from those visible to the 

 naked eye down to the faintest which his most powerful 

 telescopes could show, and fainter orbs j'et, whose lustre 

 cuuld only be recognised as milky nebulosity (resulting 

 from the combination of the light of many stars sepa- 

 rately undisceruible). Around these rich regions were 

 regions comparatively poverty-stricken, regions deserving 

 the description applied by the younger Hcrschel to the 

 spaces around the Magellanic Clouds, of which he wrote 

 that " the access to the nubecuUe is on all sides tlrt'ough a 

 desert." If his assumpti<in had been correct, the.-e 

 seeming clouds of many varied orders of stars, 

 brought into view successively with increase of 

 telescopic power, would be long cylindrical star- 

 clusters, or rather spike-shaped projections of star- 

 strewn space, hundreds of times longer than their 

 thwart breadth, and chancing by some strange accident 

 to have their axes directed exactly towards our place in 

 the star system. Unlikely, one may almost saj^ in- 

 credible, in a single case, this peculiarity would be 

 utterly impossible in several ; and the clouds so to be 

 interpreted (if Herschel's assumption were retained) are 

 many. 



Obviously we must reject this porctipiuc theory 

 of the stellar system, with the solar system for the 

 '• pole ■' of all the stellar spines. We see that the rich 

 cloud-like regions arc real clouds of stars of many varied 

 orders, and that iu each case where Herschel had 

 assumed (though only tentatively) that ho was pene- 

 trating further and further into space, he was in reality 

 only analysing more and more scrutinisingly a complex 

 cloud of stars. His position might be compared to that 

 of an observer trying to gauge our solar system from a 

 distance, who might naturally assume at first that the 

 giant planets were much further awaj- than the sun, the 

 terrestrial ]ilanets much further away than the giant 

 planets, the asteroids than the terrestrial planets, the 

 meteorites than the asteroids, the small meteors than the 

 meteorites, and the still smaller particles in comets' 

 tails than meteors ; such an observer, as soon as he re- 

 cognised the associ:'.tion of all these objects into a system, 

 would see that, instead of attributing the variety of 

 aspect within the .system ' to the variety of distance, 

 he must regard it as due to real variety of size. 

 The meteors which he had interpreted as millions of times 

 more remote than the giant planets, he would now find 

 to be in many cases close alongside of those large bodies, 

 and, on the average, no further away than the chief orb 

 in the system, the great controlling sun. In like manner 

 the faintest .stars in the gi-eat clustering regions of the 

 !Milky Way are, on the average, no further away than 

 the leading orbs in the same star-clouds (which, be it 

 noticed in passing, is by no means the same as saying 

 that the fainter stars of the stellar depths are, on the 

 average, no farther away than the more conspicuou.s). 

 The assumptions made by the elder Herschel. though 



shown as his work proceeded to be mistaken, did not pre- 

 vent his accumulated results from being most valuable. 

 But the validity of statistical methods was shown to be 

 doubtful. The assumptions of Wilhelm Struve were still 

 more improbable antecedently, and still more thoroughly 

 discredited by the evidence. He took a zone of the 

 heavens 30 degrees wide, assumed that the stars (down 

 to the eighth magnitude) might be supposed to be first 

 compressed along the mid-line of that /one, and then 

 strewn out uniformly in twenty-four sectors, into which 

 he divided the circular area enclosed by that mid-line. 

 This naturally led to a result having no validity what- 

 soever. 



The fault of all such statistical methods is that in effect 

 the}- depend on a process of averaging by which, even if 

 the initial assumptions were trustworthy, the significance 

 of all the actual peculiarities of stellar architecture 

 would be concealed. We want to have these peculiarities 

 emphasised rather than hidden. Charting alone cm do 

 this eifectually. But who can pretend to chart the whole 

 heavens to any great depth around our solar system ? 

 Struve used in his statistical inquiries about 70,000 

 stars, and I has shown iu a single eqnal-surfaee chart 

 324,000 ; but what are they among tens of millions of 

 stars within the range of Herschel's gauging telescopes ? 

 That single chart required first seven yesar of observatory 

 labour by Argelander and his assistants, then -100 hours 

 of charting by myself; yet it shows only stars down 

 to between the ninth and tenth magnitudes, and even iu 

 regard to these is affected by all the variations arising 

 from the "personality" of the different observers. The 

 ]iro]iosed photographic survey would extend very much 

 further into surrounding space, would be far more trust- 

 worthy, and would be entirely independent of " personal 

 equation." The idea is a magnificent one, and it may bo 

 hoped that the astronomers of all nations will help in 

 carrying it out. — Tiynes. 



EVOLUTION OF LANGUAGE, 



By AuxV S. Ballin. 



III.— J^ENKE-CUANGES. 



ANGUAGE may be regarded as a tool of 

 the human mind, an instrument, serving 

 two fixed purposes — namely, the expres- 

 sion and record of thought. The changes 

 iu the pronunciation of words may be 

 compared to the wearing down and 

 smoothing of the handle of such a tool 

 which renders it more easy and comfortable to work 

 with ; but there are changes of more importance than 

 these — namely, changes in the method of using the tool 

 in which it is adapted perforce to the new purposes it is 

 required to serve. As new ideas are evolved, it is found 

 necessary to express them, and to this end old words are 

 adapted, or, as it were, attached to the new meanings 

 by a process based on the principle of similarity. 

 In like manner, as I pointed out when speaking 

 of the deaf and dumb,* that their chief means of 

 communicating ideas was by indicating likeness, as by 

 touching their lips to express " red," so with verbal 

 language, new ideas are expressed by describing them in 

 terms of the old. Thus it is that the meaning of words 

 change by their beiug applied to ideas other than those 

 which they formerly expressed. The similarity which 



* Knowledge, vol. VII., in the series 

 Language." 



on " Thought and 



