ing the millions, or thousands of mil-ery; there are iron vessels on every lions, of years for which that matter ocean, and objects of every size made has existed, it has perhaps only once of iron, from the smallest nails up to become so heated, owing to circum- hundred-ton guns. There is also at stances which we may describe as acci- this moment, and every moment, a good dental or casual, as to have acquired deal of hot iron on the earth. While the ample light-dispensing power of I write, iron is doubtless flowing from a sun. It is, however, possible that blast furnaces in England, Wales, and such periods of light-radiating capacity Scotland; while I write, ingots of should have occurred more than once; white-hot Bessemer steel are being they may possibly have occurred sev- dealt with under the steam-hammer or eral times throughout the ages of time in the rolling-mills; while I write, past. Nor is it likely that the last phe- horse-shoes are being forged, and, at nomena of this kind have yet arrived. | each moment, in one way or another, The sun, after the lapse of uncounted years, will lose all its heat and pass into a black, dark mass. In that form it may endure for an epoch so protracted that the spell during which it has acted as the luminary to our system will appear but a moment in comparison with the dark ages which succeed the solar splendor. But we can conceive that the darkness, which is the doom of our system, need not necessarily be eternal so far as its materials are concerned; it may be that again in the course of its wanderings through space, the tide of chance may at length bring the dark and tremendous globe so near some other orb that another collision should take place with appalling vehemence. The solid materials shall again become transformed into a stupendous glowing nebula, and then, in the course of the tedious contraction of this nebula, another protracted period of brilliance will diversify the career of this great body, and may last long enough for the evolution of planets and of whole races of highly organized creatures. The essential point for our present consideration must not be misunderstood. A little reflection will show that any periods of brilliance must be regarded as exceptional periods in the history of each body. Think, for instance, of all the iron on the surface of the earth. There is the iron in the ore; there are the great stores of pigiron lying ready for use; there are the vast bridges which span our rivers and straits; there are the thousands of miles of railway lines; there are the countless wheels and pieces of machin

pieces of iron of every temperature could be found, from those which are as cold as the iron apparatus used by Professor Dewar in his experiments in the liquefaction of air, up to the glittering melted steel which is poured from the tilted converter. But, it must be admitted that the highly heated pieces of iron bear a very small proportion indeed to the total mass of iron in the world at any moment. No doubt there are many tons of iron now white-hot, but there are many millions of tons of iron which was once white-hot, and is now no warmer than the air around it. At certain phases in its history every piece of iron has to undergo the operation of being raised to incandescence, or even of being transformed into a liquid. But the laws of cooling are such that, as soon as the opportunity is afforded, the iron parts with its redundant heat and returns to a stable condition, in which it is at the temperature of the air. Now, suppose that some percipient being, who was viewing this earth from above, could only see iron when it was red-hot or white-hot, but that he had every facility for perceiving such iron as happened to be in this condition.

With such faculties he would, no doubt, be able to discern here and there a stream of molten iron issuing from a blast furnace, or perhaps to witness the operation of the forging of an anchor under the steamhammer, to watch the rolling of the plates for an armor-clad, or to see the more humble operations of the blacksmith or the nail-maker. But he would surely form an entirely erroneous im

incident in the career of the body from which the light emanates; and when we further believe, as believe we must, that for each one star which we can

pression as to the quantity of iron on luminosity is a characteristic. In such this earth, or as to the extent in which cases only will the orbs be visible. it was employed in the varied purposes The instructed astronomer will, thereof the arts, if he concluded that there fore, believe that the non-visible orbs were no iron on our globe at all except must be hundreds, thousands, or per, that which happened at the moment to haps millions of times more numerous be in that particular incandescent state than those which he can see. When in which alone it was visible to him. we remember that, by our telescopes If he were gifted with reasoning powers and on our photographs, we can discern he would say, "It is quite true that I something like one hundred million can only see the iron while it is red-hot, | luminous stars in the sky; when we but I know that for iron to be red-hot remember that every one of these is on the earth's surface is an exceptional the indication of a wholly exceptional and abnormal condition of a very temporary or intermittent character. No doubt, every piece of iron may have to be red-hot once, or more than once, but the total duration of such phases of thus see there must be a stupendous incandescence are quite insignificant under ordinary circumstances when compared with the periods in which the iron is cold and invisible. I, therefore, cannot refuse to believe that there must be an amount of iron on the earth which I do not see, but which bears a proportion to that which I do see in the ratio of thousands or millions to one." Precisely similar is the way in which the astronomer who is properly familiar with the theory of probabilities will approach the study of the stars. He will reflect that each mass of matter through the period of its existence must be cold and invisible for by far the greater part of the time; he will reflect that on

number of invisible masses, then, indeed, we begin to get some notion of the extraordinary multitude in which material orbs are strewn through space. The theory of probabilities declares to us with a certainty, hardly, in my opinion, inferior to that of optical demon, stration, that even within the distance which can be penetrated by our telescopes the visible stars cannot form the hundredth, probably not the thousandth, perhaps not the millionth part of the total quantity of matter.

On the question as to whether space is finite, our observations with the telescope have but little information to give. The question here involved is rare occasions, separated by rather of a metaphysical complexion. intervals of appalling length, certain The extent of space depends more exceptional conditions arise by which upon the facts of consciousness than this dark piece of matter may be so kin- upon those of astronomical observation, dled that, for an epoch, long it may be It may, perhaps, simplify the discusin years but brief indeed when com- sion of the subject if we first of all pared with the span of told existence, consider the question as to whether the the body would glow as a star. Pro- quantity of matter in the universe may vided with this conception let us look be presumed to be infinite or not. We on the universe with its millions of can put the question into a perfectly orbs. These orbs will be found in concise form by reflecting that every every phase possible to such bodies; particle of matter, whether solid, liquid, but the enormous majority of them or gaseous, is composed of molecules. must, in accordance with the principles No doubt these molecules are so númer just laid down, be in the dark and in-ous that even in the air we breathe the visible state. Out of some millions it may perhaps be concluded that, at any particular moment, a dozen or so might, by accidental circumstances, be in those phases of their several careers in which

capacity of a lady's thimble would contain a multitude of molecules so great that it has to be enumerated by billions. But we are not at present merely cons cerned with the actual number of mole4267

you can commence again. It appears almost equally impossible to suppose that the journey could be carried on forever as to suppose that it could ever be brought to an end. It was, however, long ago shown by Kant that space was rather to be regarded as a form in which the human mind was compelled to regard objects than as a self-existing fact of external nature. We have no power in our own consciousness to surmount the difficulties of conception to which I have referred. They arise from the conditions of our mental constitution, and reasoning about space will do no more to remove its mysteries than it will suffice to give to the man born blind a notion of the color scarlet. But mathematicians, while fully aware of the imperfection of their powers of conception as regards the facts of space, are still enabled to frame a perfectly consistent theory according to which the observed phenomena of nature can be presented within a space which is finite in dimensions. They are even able, as it were, to lay their finger upon the exact point in which the subjective difficulty has

cules that may exist in the atmosphere, | boundary, the imagination will equally even in its whole extent, or in the suggest that there is something on the whole earth, or in the whole sun. Let other side of that boundary from which us try to conceive the number of molecules that are present in all the stars, bright and dark, which exist not only within those regions of space accessible to our telescopes, but elsewhere as well. In short, let us try to conjure up in our imagination the kind of figures which are to express the total number of molecules in the universe. Is that number finite, or is it not? This is, perhaps, one of the most fundamental questions in nature which could possibly be proposed. Let us consider the consequences which would follow from adopting a negative answer to this question. If we suppose that the number of molecules was indeed infinite, then we are necessarily forced to admit at once that space must be infinite too; for had space any boundary, then, since the molecules do not admit of being crowded together beyond a certain extent, it would be impossible that they could exist in infinite abundance. Adopting the sound principle that we need not assume more than is necessary to explain the phenomena exactly presented by our consciousness, it seems to me to be clear that the number of molecules of matter in the universe arisen. must be finite. The row of figures I must here be permitted to refer to which would express that number, a point in connection with the elements whatever it may be, is the most remarkable descriptive constant which the universe possesses. It matters not for our present argument what may be the number of figures by which this number can be expressed. It may not be too large to be written even on the thumb-nail by the compendious method of notation now in general use.

of Euclid. The beginner who studies this work commences, of course, by learning the axioms, and reads without any feeling of discontent or querulousness such venerable truths as that "the whole is greater than its part." But, after a number of propositions of this eminently unquestionable but somewhat puerile kind, he is suddenly brought up Let us next see whether we can learn by the famous twelfth axiom in which anything as to the extent of space itself. | Euclid lays down the theory of parallel It is apparent that we seem to be in lines. Here is a statement of a radithe presence of about equal difficulties cally different kind from such assertions whether we attempt to think of space as that "if equals be added to equals as finite or infinite; for, imagine that the wholes are equal." In fact, Euyou go up in a straight line into the clid's notion of parallel lines is so far sky, and on, and on, and on, in thought from being an axiom of the same charfor millions of miles, it would seem that acter as these other propositions that it the journey ought to be endless; for, is quite possible to doubt its truth withsupposing that you try to conceive a out doing any violence to our conscious

inally started need not involve a journey of infinite length. If we assume Euclid's twelfth axiom to be true, then no doubt the traveller can only get back to the point from which he started as the result of a journey of infinite length which will have occupied an infinite time. But now suppose that Euclid's twelfth axiom be not true, or suppose that, what comes to the same thing, the three angles of a triangle are not indeed. equal to two right angles, then the jour

ness. The principle assumed in the twelfth axiom cannot be proved, and it has been well remarked, that it indicates the supreme genius of Euclid to have expressed this particular axiom in such language as challenges at once the attention and the caution of the student. It may, however, be said that nearly all our difficulties in connection with the conceptions of space take their origin in the ambiguities which arise from the assumption which the twelfth axion implies. Some modern mathe-ney may require neither an infinite maticians have gone so far as to deny lapse of time nor an infinitely great the existence of this axiom altogether speed before the traveller regains his as a truth of nature, and it is most im- original position, even though he is portant to notice that when free from moving in a straight line all the time. the embarrassment which the assump- Space is thus clearly finite; for a partion of Euclid involves, a geometry ticle travelling in a straight line with emerges which removes our difficulties. uniform speed in the same direction is It seems to show that space is finite never able to get beyond a certain limrather than infinite, so far as we can ited distance from the original position, assign definite meaning to the words, to which it will every now and then but it would lead me into matters some- return. Those who remember their what inconvenient for these pages if I Euclid may be horror-struck at the herwere to pursue the matter with any esy which suggests any doubt as to the further detail. I may, however, say sanctions by which they believe in the that it can be demonstrated that all equality of the three angles of a triknown facts about space are reconcil-angle to two right angles. Let them able with the supposition that if we follow a straight line through space, using for the word straight the definition which science has shown properly to belong to it, that then, after a journey which is not infinite in its length, we shall find ourselves back at the point from which we started. If any one should think this a difficulty, I would recommend him to try to affix a legitimate definition to the word straight. He will find that the strictly definable attributes of straightness are quite compatible with the fact that a particle moving along a straight line will ultimately be restored to the point from which it departed.

It is quite true that this seems to be a paradox, but it will not be so considered by the geometer. The truth it implies is indeed quite a familiar doctrine in modern geometry. But what is not so familiar to mathematicians is that the restoration of the travelling particle to the point from which it orig

know now that this proposition has never been proved, and never can be proved, except by the somewhat illogical process of first assuming what is equivalent to the same thing, as Euclid does in assuming the twelfth axiom. Let it be granted that this proposition is to some very minute extent an untrue one; there is nothing we know of which shows that such a supposition is unwarrantable; no measurements that we can make with our instruments; no observation that we can make with our telescopes; no reasonings that we can make with our intellect, can ever demonstrate that the three angles of a triangle may not as a matter of fact actually differ from the right angles by some such amount as, let us say, the inillionth part of a second. This does no violence to our consciousness, while it provides the needed loophole for escape from the illogicalities and the contradictions into which our attempted conceptions of space otherwise land us. ROBERT BALL.

From The Cornhill Magazine.

THE SCILLIES AND THE SCILLONIANS.

useful herb which is to roast duck what the soul of a man is to his body. The words Daffodil, Narcissus, Mackerel, New Potatoes, or Wreck may also be tendered as substitutes more or less pleasant and appropriate; and all preferable to Scilly.

It is perhaps unfortunate for the natives of these isles that by the exigencies of English pronunciation they are in some peril of being bracketed by the ignorant with the inmates of our lunatic asylums. But in fact the islanders In truth, however, no error could be might if they pleased revolt upon good more radical than to imagine the Scilgrounds against the accepted appella- lonians deficient in wit. We know but tion of their home-land. It is affirmed little about them in the olden time; by experts that in the old time the except that the Romans used their isles name was pronounced "Skilly.” This, as a repository for Cornish tin, and perthough to the novel reader reminiscent haps burrowed locally also for the same of thin gruel, is at least more dignified mineral. But in the last few generathan "Silly." The word is derived tions the islanders have shown their from the Cornish "skoly" or "skully," abilities as smugglers, rogues, shipto scatter. This is fairly significative builders, pilots, and market gardeners of the hundred or two of black rocks in a way that ranges them far beyond and green islets which form the group, spread as they are over a broad surface of water. But other derivations are also in the field. There is "sylla," a conger eel, or "scylly," to separate; either of which may be at the bottom of the nomenclature of the interesting little archipelago.

the borders of imbecility. One half expects to find them an indolent little community, enjoying their mild climate after the manner of the people of Hawaii. But I had not been a day in St. Mary's ere I had changed my opinion in this matter, and at the end of a week methought a little of their energy might profitably be transferred to some of our mainland towns.

It is, of course, easy to reach the isles. During the early weeks of sum

Here, then, is scope for the employment of the county councillors, whose recent institution in the capital of the islands has caused so much suspicion. By getting a stout lever under estab-mer there is a steamer almost daily lished custom, the councillors may do wonders, and in a year or two effectually remove the reproach which has hitherto for long lain upon the archipelago. They will also thereby perchance justify themselves and their existence in the regard of their fellow islanders. These view them as a pretext for a new rate merely. The council chamber is over the butchers' stalls in Hugh Town market-place. It is a suggestive location. Blood has been ere now spilt for more trivial grievances than this which has taken possession of the minds of the people. But let the councillors accommodate their views and actions to their situation, and all may yet be well. Let them rechristen the islands without delay. If the name must relate to their natural products, would the transition from "Scilly" to Sage" be too abrupt? For in the

from Penzance to St. Mary's. This is more for the convenience of the fish trade, and the Billingsgate gentlemen who have it in charge, than for the visitors or the mails. Still, visitors may benefit by it though at some personal cost. The Atlantic off the Land's End is seldom as smooth as it might be. The perfume of stale fish-baskets is decidedly disagreeable. Thus it is advisable for the person who travels to the isles during the mackerel season to take a robust stomach with him; and to be heartily unconscious of bad smells. On these conditions, there is much to enjoy in the little trip of three or four hours. The Cornish coast is viewed panoramically, and for the brief interval during which one is out of sight of land it is as if one were in mid-passage between Liverpool and New York.

Very soon, however, the low rocks of

local gardens I have seen much of that the isles lift their heads above the