Jax. 2, 18t5.] 



• KNOWLEDGE ♦ 



food is quite unnecessary ; and also that men and women 

 who emulate the aforesaid sheep to the mild extent of con- 

 suming daily about two ounces of animal tissue combined 

 with six ounces of water, and dilute tliis with s-ucli weak 

 vegetable food as the potato, are not measurably altered 

 thereby so far as physical health is concerned. 



On economioLil grounds, however, the ditl'erencft is 

 enormous. If all Eiigli>hincn were vegetarians tlie whole 

 aspect of the country would be chnnged. It would be a 

 land of gardens and orchards, instead of gradually reverting 

 to prairie grazing ground as at present. The unenn)loyed 

 miserables of our great towns, the inhabitants of our vinion 

 workhouses, and all our rogues and vagabonds, would find 

 ample and suitable employment in itgriculture. Every acre 

 of land would require three or four times as much labour 

 as at present, and fte.l tivc or six times as unny people. 



No sentimental exaggeration is demanded for tlic recom- 

 mendation of such a reform as tlii?. 



I must apologise for this digression, as it has prevented 

 me from closing this series with this paper, as f intended. 

 In my next, -nhich really will conclude, 1 shall d('.sci'ib(! 

 some experiments I have recently made on the preparation 

 of vegetable food. 



NEEDED STAR SURVEYS. 



By Eichard A. Puoctor. 



IN my article on Sir W. Ilerschel's two methods of 

 gauging the star-depths, I showed that, in a sense, 

 both methods failed, one obviously to himself, the other as 

 tested by his own method of reasoning. But let us consider 

 what we mean when we say that either method failed, and 

 then note what each method showed, what other methods 

 are suggested by the results of applying those, and lastly 

 what further plans are available for the survey of the star- 

 depths. 



Herschel's first method of gauging the heavens was based 

 on the assumption that the greater the number of .stars seen 

 ■with a given telcicope in one and the same direction, the 

 greater the e.xtent of the sidereal universe in that direction. 

 It can only be Siid to have failed in tliu respect, that it 

 showed the incorrectness of the assumption on which it was 

 based. Herschel found that a great increase in the number 

 ■of stirs seen in particular directions may arise — and in 

 many cases certainly does arise — from the clustering of 

 great numbers of stars in their particular regions of space 

 — a condition of things of which his preliminary assumption 

 bad taken no account. 



But while this involved the utter failure of the process 

 of measurement which he had proposed to apply to the 

 stellar universe, it by no means implied the failure of his 

 observations to reveal any new truth. Ou the contrary, 

 the very circumstance that he had to give up his precon- 

 ceived idea of stellar distribution shows that a quite un- 

 expected discovery had rewarded his star-gauging labours 

 He had been able to demonstrate the clustering of stars 

 in particular regions of space, and therein lay a discovery 

 of extreme interest. 



Herschel's second method of gauging the heavens was 

 based on the assumption that the greater the telescopic 

 power required for the resolution of the milky light of the 

 Galaxy into discrete stars, the greater the extent of the 

 t idereal universe in the direction thus explored. This 

 method also failed; but it only failed in l/iis sense, that 

 it showed the assumption Herechel had thus made to 

 be incorrect In some regions of small extent he found 

 the resolution of the milky light to begn with his lowest 



powers and ccuitinue until his highest were used, milky 

 light even then still rcimiiniug unresolved. And although 

 ho did not himself note the point, it is numifest tiiat 

 this, if his original assumption had been sound, would 

 have signified the cxistenct! of long spike-shaped projections 

 of stars from the sidereal system, all these proj(>ctions, by 

 an incredible chance, being directed exiictly from the solar 

 system. As such a supposition ciinnot be accepted for an 

 instant, it is manifest (lluuigh llersclu'l, then in extreme 

 old age, did not notice this), tliat there must be a clustering 

 of stars of many orders of real magnitude within particular 

 regions of space, — a condition of things of which Herschel's 

 second preliminary assumption had taken no account. 



But here also, while the complete failure of tliis second 

 process of measurement was involved, this failure by no 

 means implied the failure of Herschel's observations to 

 reveal new truth. Here, as in the other case, the very cir- 

 cumstance that a certain idea of stellar distribution had to 

 be given up, showed that a di'^covery of importance had 

 rewarded Herschel's laliours. He had been able to show 

 that the clusterings of stars already demonstrated was not 

 a clustering of .stars nearly equal in magnituJe, but of 

 stars differing enormously in real size. Some of the 

 rounded clusters thus examined by Herschel are so limited 

 in extent that, assigning to them a roughly rounded real 

 form (inferable from their obviously rounded apparent 

 form), w-e see that the farthest ]>irts of these clusters are 

 not farther away than the nearer ])arts in greater degree 

 than as 100 is greater than 99. But within these narrow 

 limits of real distance llerfchel found ciifl'i'rences of stellar 

 size and resolvability, through some eighteen star magni- 

 tudes, which would have corresponded (had his assumption 

 been true) to distances diti'ering much more tlian a hundred 

 differs from unity. The discovery that within rounded 

 regions of the stellar universe there may exist so many 

 orders of suns, the largest exceeding the smallest thousands 

 of times in volume, was of extreme interest, and threw an 

 entirely new liglit on the architecture of the sidereal 

 system. 



In like manner it is to be noticed that Herschel's obser- 

 vatiom of star-clouds or nebuUe, although by no means to 

 be interpreted as ho had at first supposed, are most im- 

 portant in their bearing on our ideas respecting the struc- 

 ture of the sidereal system. He regarded the nebuhe as 

 outlj'ing universes resembling our own galaxy, — a grand 

 idea justifying what is said on his tombstone, that he had 

 broken through the boumls of our heavens, — Codonun 

 perrupit daustra. It is however certain in reality all 

 these star-clouds are within the limits of our sidereal 

 universe. Herschel's own principle of interpreting his 

 observations, though inadequate and inexact, suflices to 

 prove so much as this. It is certain that with his most 

 powerful tflescope he was unable to reach the limits of our 

 galaxy ; U is manifest, therefore, that he could not see 

 with them the individual stars or even the milky li^jht of 

 galaxies lying far beyond those limits. Therefore all the 

 nebulai observed by him were within these limits. There 

 is no possibility of escaping this conclusion, unlc-s we 

 admit the possibility that there exist outside our galaxy 

 others consisting of enormously larger and more brilliant 

 .stars — stars thousands of times larger than Siiius and 

 Vega, which are themselves at least a thousand times 

 larger than our great and glorious sun. 



Of course, all these results may be said to have been proved 

 at one stroke by Sir John Herschel's observations of the 

 Neheculce or M-igellanic Clou'ls. He found in tliose rounded 

 regi<ms (i) immense nniubers of stars, indicating enormous 

 range in distance if Lis father's first giuging principle is 

 accepted ; (ii) immense varieties in the .sizes of stars (from 



