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FIG. 61.
IT is a well-established fact that light and heat radiate equally in all directions. When the sun is on the outer circle, B, fig. 60, as it is on the 21st of December, it is known that the light gradually diminishes, until at or about 20 degrees from the northern centre, it shades almost imperceptibly into twilight and darkness. If, then, we take from B (fig. 60), to the arctic circle, 1, 2, 3, as radius, and describe the circle 4, 5, 6, we have represented the whole extent of sun or daylight at a given moment on the shortest day. When, as on the 21st of June, the sun by gradually contracting its path, has arrived at the inner circle, A, the same length of radius will produce the circle 7, 8, 9, which represents the extent of daylight on the longest day. It will be seen by the diagram that, on the shortest day, the light terminates at the arctic circle 1, 2, 3, leaving all beyond in darkness; and as the sun moves forward in the direction of the arrows, the edge of the circle of light continues, during the whole of its course, to fall short at this circle. Hence. although it is daylight
all over the rest of the earth in twenty-four hours, the centre, N, is left in continual darkness. But when, in six months afterwards, the sun is on the inner circle, A, the light extends beyond the arctic circle, 1, 2, 3; and as it moves in its course, the centre, N, is continually illuminated. These changes will be better understood by reference to the diagrams, figs. 61 and 62.
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FIG. 61.
In fig. 61, the circle A, A, A, represents the sun's daily
path on December 21st, and B, B, B, the same on June 21st; N, the northern centre; S, the sun; and E, the position of Great Britain; the figures, 1, 2, 3, the arctic
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FIG. 62.
circle; and 4, 5, 6, the extent of sun-light at noon of that day. The sun, S, describes the circle A, A, A, on the 21st of December in one day, or twenty-four hours. Hence, in that period, mid-day and midnight, and morning and evening twilight, occur to every part of the earth except within the arctic circle, 1, 2, 3. There it is more or less
in darkness for several months in succession, or until the sun, by gradually coming nearer to the inner circle, throws his light more and more over the centre. The arc of light at 4, is the advancing or morning twilight, and 6, the receding or evening twilight. At every place underneath a line drawn across the circle of the sun's light, 4, 5, 6, through S, to N, it is noonday; and beyond the northern centre, on the same line, it is midnight.
It will now be readily understood that as the sun moves in the direction of the arrows, or from right to left, and completes the circle, A, A, A, in twenty-four hours, it will produce in that period, and where its light reaches, morning, noon, evening, and night, on all parts of the earth in succession. As the sun's path now begins to contract every day for six months, or until the 21st of June, when it becomes the circle, B, B, B, it is evident that the same extent of sunlight as that which radiates from the outer circle, A, A, A, will reach over or beyond the northern centre, N, as shown in the diagram, fig. 62; when morning, noon, evening, and night, occur as before; but the light continuing, during the daily motion of the sun, to reach over the northern centre, that centre will, be continually illuminated for several months together, as before it was in constant darkness. It will be seen also by reference to the diagram that when the sun is on the outer path, A, the portion of the disc of light which passes over England is much smaller than when it is on the inner path, B. Hence, the short days and winter season from the first position, and the longer days and summer season from the second. Thus day and night, long and short
days and nights, morning and evening twilight, winter and summer, the long periods of alternate light and darkness at the northern or polar centre of the earth, arise from the expansion and contraction of the sun's path, and are all a part of one and the same general phenomenon.
The whole of these explanations have reference only to the region between the sun and the northern centre. It is evident that in the great encircling oceans of the south, and the numerous islands and parts of continents, which exist beyond that part of the earth where the sun is vertical, cannot have their days and nights, seasons, &c., precisely like those in the northern region. The north is a centre, and the south is that centre radiated or thrown out to a vast oceanic circumference, terminating in circular walls of ice, which form an impenetrable frozen barrier. Hence the phenomena referred to as existing in the north must be considerably modified in the south, For instance, the north being central, the light of the sun advancing and receding, gives long periods of alternate light and darkness at the actual centre; but in the far south, the sun, even when moving in his outer path, can only throw its light to a certain distance, beyond which there must be perpetual darkness. No evidence exists of there being long periods of light and darkness regularly alternating, as in the north. In the north, in summer-time, when the sun is moving in its inner path, the light shines continually for months together over the central region, and rapidly develops numerous forms of animal and vegetable life.
"Beyond the 70th degree of latitude not a tree meets the
eye, wearied with the white waste of snow; forests, woods, even shrubs have disappeared, and given place to a few lichens and creeping woody plants, which scantily clothe the indurated soil. Still, in the farthest north, Nature claims her birthright of beauty; and in the brief and rapid summer she brings forth numerous flowers and grasses, to bloom for a few days, to be again blasted by the swiftly-recurring winter." 1
"The rapid fervour of an arctic summer had already (June 1st) converted the snowy waste into luxuriant pasture-ground, rich in flowers and grass, with almost the same lively appearance as that of an English meadow." 2
Wrangell tells us that "Countless herds of reindeer, elks, black bears, foxes, sables, and grey squirrels, fill the upland forests; stone foxes and wolves roam over the low grounds; enormous flights of swans, geese, and ducks, arrive in spring, and seek deserts where they may moult, and build their nests in safety. Eagles, owls, and gulls, pursue their prey along the sea-coast; ptarmigan run in troops among the bushes; little snipes are busy among the brooks and in the morasses; the social crows seek the neighbourhood of men's habitations; and when the sun shines in spring, one may even sometimes hear the cheerful note of the finch, and in autumn, that of the thrush."
Thus it is a well ascertained fact that the constant sunlight of the north develops, with the utmost rapidity, numerous forms of vegetable life, and furnishes subsistence for millions of living creatures. But in the south, where the sunlight never dwells, or lingers about a central region, but rapidly sweeps over sea and land, to complete in
twenty-four hours the great circle of the southern circumference, it has not time to excite and stimulate the surface; and, therefore, even in comparatively low southern latitudes, everything wears an aspect of desolation.
"On the South Georgias, in same latitude as Yorkshire in the north, Cook did not find a shrub big enough to make a toothpick. Captain Cook describes it as 'savage and horrible. The wild rocks raised their lofty summits till they were lost in the clouds, and the valleys lay covered with everlasting snow. Not a tree was to be seen; not a shrub even big enough to make a toothpick. Who could have thought that an island of no greater extent than this (Isle of Georgia), situated between the latitude of 54 and 55 degrees, should, in the very height of summer, be in a manner wholly covered many fathoms deep with frozen snow? The lands which lie to the south are doomed by Nature to perpetual frigidness--never to feel the warmth of the sun's rays; whose horrible and savage aspect I have not words to describe.' The South Shetlands, occupying a corresponding latitude to their namesakes in the north, present scarcely a vestige of vegetation. Kerguelen, as low as latitude 50 degrees south, boasts eighteen species of plants, of which only one, a peculiar kind of cabbage, has been found useful, in eases of scurvy; while Iceland, 15 degrees nearer to the pole in the north, boasts 870 species. Even marine life is sparse in certain tracts of vast extent, and the sea-bird is seldom observed flying over such lonely wastes. The contrast between the limits of organic life in arctic and antarctic zones is very remarkable and significant. Vegetables and land animals are found at nearly 80 degrees in the north; while, from the parallel of 58 degrees in the south, the lichen, and such like plants only clothe the rocks, and sea-birds and the cetaceous
tribes alone are seen upon the desolate beaches." "M‘Clintoch describes heads of reindeer--a perfect forest of antlers, moving north in the summer. . . . The eider duck and the brent goose through the air; the unwieldly family of the cetacea through the waters; the arctic bear upon the ice; the musk ox and reindeer along the land--all wend their way northward at certain seasons. . . . Now these indications are absent from the southern zone, as is also the inhabitation of man. The bones of musk oxen, killed by the Esquimaux, were found north of the 79th parallel; while in the south, man is not found above the 56th parallel of latitude." 1
These differences in the north and south could not exist if the earth were a globe, turning upon axes underneath a non-moving sun. The two hemispheres would at the same latitudes have the same degree of light and heat, and the same general phenomena, both in kind and degree. The peculiarities which are found in the south as compared with the north, are only such as could exist upon a stationary plane, having a northern centre, concentric with which is the path of the moving sun. The subject may be placed in the following syllogistic form.
The peculiarities observed in the south as compared with the north, could not exist upon a globe.
They do exist, therefore the earth is not a globe.
They are such as could and must exist upon a plane.
They do exist, therefore the earth is a plane.
It will also be seen by a careful study of the diagram fig. 61, that, as the sun-light has to sweep over the great
southern region in the same time, 24 hours, that it takes to pass over the smaller region of the north, the passage of the light must of necessity be proportionably more rapid; and the morning and evening twilight more abrupt. In the north the light on summer evenings seems as it were unwilling to terminate; and at midsummer, for many nights in succession, the sky is scarcely darkened. The twilight continues for hours after visible sunset. In the south, however, the reverse is the case, the day ends suddenly, and the night passes into day in a few seconds. A letter from a correspondent in New Zealand, dated, "Nelson, September 15th, 1857," contains the following passages:
"Even in summer, people here have no notion of going without fires in the evening; but then, though the days are very warm and sunny, the nights are always cold. For seven months last summer, we had not one day that the sun did not shine as brilliantly as it does in England in the finest day in June; and though it has more power here, the heat is not nearly so oppressive. . . But then there is not the twilight which you get in England. Here it is light till about eight o'clock, then, in a few minutes, it becomes too dark to see anything, and the change comes over in almost no time."
In a pamphlet by W. Swainson, Esq., Attorney General for New Zealand, (Smith, Elder, & Co., Cornhill, London, 1856,) among other peculiarities referred to, it is said that at Auckland, "of twilight there is little or none."
Captain Basil Hall, RN., F.R.S., in his narration says:
"Twilight lasts but a short time in so low a latitude as 28
degrees, and no sooner does the sun peep above the horizon, than all the gorgeous parade by which he is preceded is shaken off, and he comes in upon us in the most abrupt and unceremonious way imaginable."
The motion of the sun over the vast southern region, wherein lies Australia and New Zealand, would also give shorter days in the south than in the north, and this is fully corroborated by experience. In the pamphlet above referred to, by Mr. Swainson, the following words occur:
"The range of temperature is limited, there being no excess of either heat or cold; compared with the climate of England, the summer of New Zealand is but very little warmer though considerably longer. . . . The seasons are the reverse of those in England. Spring commences in September, summer in December, autum in April, and winter in June. . . . The days are an hour shorter at each end of the day in summer, and an hour longer in the winter than in England."
From a work on New Zealand, by Arthur S. Thompson, Esq., M.D., the following sentences are quoted:---
"The summer mornings, even in the warmest parts of the colony, are sufficiently fresh to exhilarate without chilling; and the seasons glide imperceptibly into each other. The days are an hour shorter at each end of the day in summer, and an hour longer in winter than in England."
In the Cook's Strait Almanack for 1848, it is said:
"At Wellington, New Zealand, December 21st, sun rises 4 h. 31 m., and sets at 7 h. 29 m., the day being 14 hours 58 minutes. June 21st, sun rises at 7 h. 29 m., and sets at 4 h.
[paragraph continues] 31 m., the day being 9 hours and 2 minutes. In England the longest day is 16 hours 34 minutes, and the shortest day is 7 hours 45 minutes. Thus the longest day in New Zealand is 1 hour and 36 minutes shorter than the longest day in England; and the shortest day in New Zealand is 1 hour and 17 minutes longer than the shortest day in England."
Another peculiarity is, that though the days are "warm and sunny, the nights are always cold:" showing that although the altitude of the sun is greater, and therefore calculated to give greater heat, its velocity and mid-night distance are much greater than in England, and hence the greater cold of the nights. It is again insisted upon that these various peculiarities could not possibly exist in the southern region, if the earth were a globe and moved upon axes, and in an orbit round the sun. If the sun is fixed, and the earth revolves underneath it, the same phenomena would exist at the same distance on each side of the equator; but such is not the case! What can operate to cause the twilight in New Zealand to be so much more sudden, or the nights so much colder than in England? The southern "hemisphere" cannot revolve more rapidly than the northern! The latitudes are about the same, and the distance round a globe would be the same at 50° south as at 50° north, and as the whole would revolve once in twenty-four hours, the surface at the two places would pass underneath the sun with the same velocity, and the light would approach in the morning, and recede in the evening in exactly the same manner, yet the very contrary is the fact! The differences are altogether incompatible with the doctrine of the earth's
rotundity; but "the earth a plane," and they are simple "matters of course." Upon a fixed plane underneath a moving sun, these phenomena are what must naturally and inevitably exist; but upon a globe they are utter impossibilities.
Some have objected to the conclusion here drawn, on the ground that the latitude of New Zealand is considerably less than that of England; but the objection falls before. the fact that the abruptness of twilight and the coldness. of the summer nights are observed far out south beyond New Zealand. The author cannot here quote from any recognised work, but he has often been assured that this, is the common experience of navigators, and especially of whaling crews, who often wander over the vast waters beyond the latitude of 50 degrees. A remarkable illustration of this experience occurred some years ago in Liverpool. At the termination of a lecture, in which this subject had been discussed, a sailor requested leave to speak, and gave the following story:--
"I was once confined on an island in South Tasmania, and had long been very anxious to escape; one morning I saw a whaling vessel in the offing, and being a good swimmer, I dashed into the sea to reach it. Being observed from the ship, a boat was sent out to pick me up. Immediately I got on board, we sailed away directly southwards. There happened to be a scarcity of hands, and I being able-bodied, was at once put to work. In the evening I was ordered aloft, and the captain cried out 'Be quick, Jack, or you'll be in the dark!' Now the sun was shining brightly, and it seemed far from the time of sunset, and I remember well that I looked at the captain, thinking he must be
a little the worse for grog. However, I went aloft, and before I had finished the order, which was a very short time, I was in pitch darkness,--the sun seemed all at once to drop behind or below the sea. I noticed this all the time we were in the far south, whenever the sun was visible and the evening fine; and I only mention it now as corroborating the lecturer's statement. Any mariner, who has been a single season in the southern whaling grounds, will tell you the same thing."
The question, "how is it that the earth is not at all times illuminated all over its surface, seeing that the sun is always several hundred miles above it?" may be answered as follows:--
First, if no atmosphere existed, no doubt the light of the sun would diffuse over the whole earth at once, and alternations of light and darkness could not exist.
Secondly, as the earth is covered with an atmosphere of many miles in depth, the density of which gradually increases downwards to the surface, all the rays of light except those which are vertical, as they enter the upper stratum of air are arrested in their course of diffusion, and by refraction bent downwards towards the earth; as this takes place in all directions round the sun--equally where density and other conditions are equal, and vice versâ--the effect is a comparatively distinct disc of sun-light.
116:1 "Arctic Explorations." By W. & R. Chambers. Edinburgh.
116:2 Ibid.
118:1 "Polar Explorations." Read before the Royal Dublin Society.
