Tribune Extras Lecture and Letter Scries. 



as I conceive, that which is utterly beyon I OM" powers 

 of conception. Then arises the thought: If spice is 

 liiflmtL', may it not be that matter is not so, that the 

 matter which occupies spac3 is liiuitcJ. th it the 

 rceion of space occupied by matter Has its 

 boundaries 7 And you will all remember the reasoning 

 that w.is applied by Aristotle to that matter. He said : 

 If you take in all material particles ia space, a Had 

 drawn from ouo to the other is limited ; it has its two 

 ends, and 110 space can be without limits of w-iieh that 

 is true ; that evry part of it, bo at the two ends of a 

 limited line. Yot after ail, so soon as wo apply to tMa 

 matter ordinary reasoning, wo flud ourselves led 

 to a contradiction. And why should wo wonder 

 at that when we recognize the ceri .ii:i:y that there is 

 here something contrary to our powers of conception I 

 You will see that is the Idea toinsisc upon the fact that 

 as \ve deal witli these in!inki.:s wo have continually en- 

 forced upon us the knowledgj of tho fact that there is 

 something far beyond our powers of conception. And 

 you will presently see that I propose to apply that to 

 the proulem full of interest for us all. 



But t'.ien comes in an astronomical view of this ques- 

 tion of the infinity of matter. It has been shown that if 

 there, were spread throughout tho universe an infinite 

 number of suns like tho stars, spread uniformly throug'i 

 the spare, then it cau readily be shown that the wliol 

 of the heavens ought to Rio w with tho same brightness 

 as the suu's surface. It does not matter ho'.v f.ir apart 

 those suns may be. or how small their dimensions might 

 be, compared with the distance separating 

 them, still you would have the whole of 

 the heavens glowing with the glory of sunlight unless 

 light were gradually extinguished as it travels through 

 space. For let this be remembered. Any group of stars 

 of ;imi(cd extent would look as bright, wherever it were 

 placed. If you carried it away if it lay at a certain dis- 

 tancethe stars composing it would gather at a certain 

 portion apparently occupied by that group. Now, sup- 

 pose the group carried twice as far away, then 

 tho stars would only cover a part of the ap- 

 parent dimenMiins that they properly covered ; but then 

 also, the group would only look one-hundredth part of 

 tho size. And therefore although the quantity of light 

 would bo reduced in proponlon to the distance, the 

 brightness would remain unaltered. Therefore ir fol- 

 lows if you conceive space filled with an infinite number 

 Of stars. separated by any average distance, 

 however great. any certain inclosed part of 

 that space would have a certain brightness; 

 tho portion next beyond it of the same, si/B 

 would have the same brightness, and a similar portion 

 next beyond that the same. Now suppose that that 

 brightness of which I have been sp"aliiug was a 

 millionth part of the same size. lu other words, the, 

 hpaco that the sun occupies in ouo of tlnuo 

 Croups covers but tho one-millionth part of the 

 M> ice that tho whole irroup appears to occupy; 

 then the next tn-oup covers another millionth, an I 

 the next another millionth, and if you go on iniiiiit"i.\, 

 you only require to take a million of those groups t< 

 have a million times the millionth part of sunlught ; 

 therefore you have tho whole of that region glowi 

 with the plow of sunlight. And HO wo come to tho con- 

 clusion, if stars are spread inll'jl'ely through space, the 



whole heaveus ought to shine with a giow of sunlight. 

 Ir that is not the case, then we are forced to tho couclu 

 Bion that light must be extinguished as it travel* 

 through space. 



A METHOD OF EVADING Trin ASTRONOMICAL OBJEC- 

 TIONS TO INFINITY OF MATTKU. 



And yet t.htira ii a way to get over that which I had 

 thought o!, but w.ii;-h was originate:! by 5:r John 

 Herschcl. He, points to the fac: that the dimensions of 

 tho several component p irts of any system are very 

 small compared with tho distance that separates one 

 Irom the. of'er. And winm yo i pa*sto a sys'em of a 

 higher order, you flul tho dimensions of tho 

 first sv-tem are very small compared with those 

 of the next. For instance, take the solar system. Tha 

 dimensions of the earth and of.i -r p.ir;s of the soiar sys- 

 tem are very small, infinitely small, compared with the 

 li-tances that separate th * various parts of the system 

 from each other. Then agiin, tho distanc-s that sep;.- 

 ato pans ot the solar system I'rom each other aio small 

 lomparcd with the distances that separate our solai- 

 system from its neighboring systems in space. Proceed 

 to a higher order an I \ ou \\ill see that the dimensions of 

 the solar uui verso are very small compared with the dis- 

 tances that separate it trom its neighboring universe. 

 Go on in that way; curry up the order of systems higher 

 and higher without limit; and then if you apply to sys- 

 tems of that kiml if you apply to them a pro-ess of cal- 

 culation you Had that no lunger have you that result of 

 heavens that glow with tho glory of sunlight, but 

 instead of that you mav have any ord>r of brightness 

 you please, according to the relations you mav suppose 

 to exist between the parts of a system and the distances 

 ihat separate one from the other. And thus wo 

 have this curious conception of tho infinity of 

 matter occupim? space. If wo are to believe 

 in that infinity of matter wo have tins coaceptiou, that 

 it may be compared to a tree. Begin with a lower twig, 

 and travel along that twig until you come to Where it 

 joins the next twiir, and so on until you come t.o whero it 

 joins the next twij:, and you have a gradual enlarge- 

 ment; you come to a new ordur ot twig at this point; 

 you come to a branch, and then to a larger branch, and 

 so you go on from that larger order, and then you have 

 the whole tree at last, and thora an end. Bit if you be- 

 lieve In the infinity of matter, and if you choose to feel 

 that there is a continual passage from one 

 system to anotber upwards gradually increasing, or 

 downwards gradually diminishing, tuea you no 

 longer have the difficulty of which I speak, and it ap- 

 pears to me if wo accept infinite space we are almost 

 bound to accept the infinity of matter. Oihcrwiso see 

 the difficulty in which we land ourselves. Suppose that 

 occupied space his a certain Unite extent, let that ex- 

 tent be what it may, there lies outside of it an infinitely 

 greater region, so that again you have what apptvirs 

 incongruous, that you have occupied space which is iu- 

 Ihutely small in proportion to the unoccupied space. 

 The idea of the inliniio occupied space is beyond our 

 powers of conception; but, not a whic less be\ oud our 

 powers of conception is the idea of an infinite un- 

 occupied space; and ihns wo are led to believe that 

 matter is inlinite, and that an infinite <]Uautity of matter 

 occupies space. 

 INFINITY OF TIMK AS WF.LL A3 OF SPACE AND 



MATTER. 



And thus we are led to thu next point that we, have to 

 deal with, an infinity of time. We arc very naturally led 

 to pass Irom (he infinity of space to tho infinity of time, 

 in tlus way, that iho only way the human mind can be- 

 i urn- acquainted with the character of matter is by tho 

 (light of iighl. And then we recognise ihis, that, every 

 part of suace wo have not yet become acquainted 



