This comet, which last year excited so much interest, is supposed by some to be the same which appeared in the year 1737. If so, it is beyond the power of the human intellect to calculate the number of miles (millions upon millions) which it has travelled since that date; we may, however, in imagination, travel with it on one of its journeys.
Starting off then, as soon as it has made its perihelion pa.s.sage, we are carried in the course of about six months to such a distance that this comparatively insignificant world (of which nevertheless we are all anxious to get a good slice) disappears entirely from our view, and the larger planets of this system are reduced to mere specks of light. The sun itself, which here scorches us at noonday, only appears there as a very minute star, just a small yellow speck. But meantime other suns, some of them of far greater magnitude and superior brilliancy than the sun we have left behind, gradually come into sight, and some of the "nebulae," which appear to us here as so many bits of faint hazy light, some of them no larger than a crown piece, now appear to our una.s.sisted vision in all the glorious majesty of suns and worlds and systems of worlds, all revolving round each other in the most regular and systematic order; for, as Milton says in _Paradise Lost_, "Order is Heaven"s first law."
After our steed had carried us for the s.p.a.ce of about seventy years in a direct onward course through systems of worlds by us from this world unseen, we should begin to return homewards, but by a different route from that by which we went out; and we should consequently have a constantly varying scene presented to our view. How awfully grand, for instance, would be the change, as we gradually lost sight of our yellow sun, to find ourselves arriving in sight and under the influence of a sun of a rich crimson red colour, and again after a few years to find ourselves in the presence of a green or a blue sun! Yet it is more than probable that such would be the case, for the sky is spangled with suns of all colours.
In the course of about 137 years from the time when we set out we should be returned sufficiently near to this world to enable its inhabitants to catch sight of our steed"s tail. And then, after all this long journey among the stars of 137 years, we should have seen but a mere atom, just one grain of the works of Him who knows the number of the hairs of our heads, and without whom a sparrow doth not fall to the ground!
Suppose we now inquire, What is the comet"s probable business in coming amongst us once in 137 years? Are its duties those of a messenger or a scavenger, or both? It is well known that the sun is continually giving off light and heat, and consequently it must of necessity be gradually exhausting itself. It has been computed that were the ma.s.s of the sun composed of Newcastle coal, with exhaustion going on at the present rate, the whole ma.s.s would be burnt out in 25,000 years. If the sun, then, is gradually being exhausted by giving off light and heat to his family of planets, and if the planets cannot give any portion of it back to him, seeing that they are entirely dependent upon the sun for their own physical and material existence--how is the sun"s strength to be kept up so as to be equal to the demands made upon him?
It is but reasonable to suppose that the comets (of which the firmament is said to be as full as the sea is of fishes) should bring some subtle fluid of which this system is being exhausted, and at the same time collect and carry away to other systems some noxious gas or other essence of which we have a superfluity, but which might be quite essential to the well-being of some other system; and that so a sort of healthy circulation in the universe around us might be kept up.
Ought we not, therefore, to look upon the appearance of a comet with some such feelings (only in a wider sense) as we would hail the arrival of a ship from a long voyage to a foreign clime, feeling sure it must come laden with some good store for the benefit of those whose business it is to stay at home performing faithfully their own several duties in their own several spheres?
R. LANGDON.
APPENDIX VI
THE PLANET VENUS
MY DEAR NELLY-BLY,--
According to promise I send a sketch showing the different positions of the planet Venus with regard to the earth during the past few months.
I am astonished, not to say grieved, at the very great amount of ignorance and superst.i.tion which exists respecting the apparition of this planet recently as a "morning star."
If you will refer to the sketch I will try and point out the various positions.
June 13, 1887, Venus began to appear low down towards the western horizon as an "evening star," but as the evenings were then light I suppose it did not attract public attention. Daily, however, the planet for a time was seen--after sunset--higher and higher in the western sky, until August 16, when it arrived in such a position with respect to the earth that it sent towards us the greatest amount of reflected light that it is possible it can send at any given time. The planet travelling through s.p.a.ce in her orbit at the rate of sixty-nine thousand miles an hour overtook the earth (which is travelling in the same direction at fifty-eight thousand miles an hour) on September 21, when she was exactly in a straight line between us and the sun--called astronomically, "inferior conjunction." The moment she pa.s.ses this point she becomes a morning star. She still moves on and leaves the earth behind, and when she arrives at the position shown on October 28 she is at her greatest brilliancy as a morning star. From this time the planet"s distance from us is rapidly increasing, and consequently her apparent size and brilliancy are as rapidly decreasing, and she is soon altogether lost in the rays of the sun and can only be seen by the aid of a telescope.
Venus makes a complete revolution round the sun in 224 days and 17 hours, but as the earth moves in the same direction but at a slower rate the planet overtakes the earth in about nineteen months, when we have her again as an evening and morning star respectively as before, and so on continually.
And this is the Star of Bethlehem which has caused such a stir within the past two months. All sorts of ridiculous speculation and superst.i.tious nonsense have been said concerning it. Verily in this our day of rapid advancement we are almost, if not quite, as ignorant of astronomical matters as were the "wise men" of the East nearly two thousand years ago, or the natives of Zululand of the present day.
I hope I have made this plain to you; or if there is anything you do not understand, just ask the question and I will endeavour to supply the information.
Yours affectionately,
R. LANGDON.
PS.--It is rather singular that Venus rotates upon her axis in such time as to produce a Leap Year once in four years as with us.--R. L.
APPENDIX VII
SILVERTON,
_Jan. 31, 1888._
DEAR BLY,--
I thought I would send a sketch of the eclipse Annie and I stayed up to see. We had a very beautiful, clear night, not a cloud to be seen. The moon entered its eastern edge into the Penumbra at 8.29 and into the dark shadow at 9.30; and at 11 p.m. the moon was in the centre of the shadow or totally eclipsed, but we could still see it appearing like a large orange and we could see all the princ.i.p.al craters and mountains through the shadow, and I was very interested to watch the stars disappear one after another behind the edge of the moon. Of course I have not shown the sun in the sketch because there is not room, but you must imagine the sun to be about the size of a round table a good distance away to the left of the earth.
Now I will try and explain to you what the Penumbra is and how it is produced. It is produced simply because the sun is so much larger than the earth, and you can make a little experiment and show Freddy and William how it is done. Place two lighted candles or lamps about the width of this paper apart which will represent the sun, then a little way off on a white cloth on the table place a teacup upside down which will do very well to represent the earth, then you will have the black shadow of the Penumbra or half shadow on each side of it. A sixpence will represent the moon, which you can slide gradually across the shadows, and you will have the eclipse to a "t."
It is necessary to have two candles or lamps because the sun is so much greater than the earth and the two candles" light combined represents the sun"s light. A small orange perhaps would represent the earth as well or better than a teacup, because the shadow of a cup would not run out to a sharp point, but that of an orange would. That would not matter much either way, only Freddy would most likely be asking the question and you would not be able to answer him.
Your affectionate
DAD.
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