Coming Eclipses

Southern Cross, Volume 2, Issue 1, 7 April 1894, Page 11

Coming Eclipses

FACTS AND THEORIES. (contributed) It is possible to observe 70 eclipses on the earth during a period of 18 years. Of these 29 are lunar and 41 solar. After a period of 18 years similar -eclipses will occur, as after a circuit ;a clock will repeat what it did 12 hours before. The Chaldeans discovered this. The most ancient solar eclipse was recorded by Heroditus 610 years before Christ, during a battle between the Lydians and Medes. It soon ended the battle. The number of solar eclipses exceed* the lunar, bu * t hey are seen over a much more li.n >.ed space. The dark cone of a sola. eclipse is only about 30 miles in i.ameter, and a solar ■eclipse can only be total for some four minmes in one place. The ■ earth’s shadow at the mean distance ■of the moon is two-and-a-fifth times larger than juII moon, ie., has a diameter of 4928 miles, and the point of this cone is three times as far off ss the moon. 8o the moon can be darkened for more hours than the Sun can be for minutes. To examine the shadow the earth -would throw draw a circle whose .Tadius would be 112 times the length ■of the line in- ended to represent the ■earth’s radius. Draw from the centre •of this circle O a line jrerpendicular Ibo diameter and of a length equal to :23,984, ie., tii--' earth's diameter.

This length is the sun’s distance from the earth, expressed in terrestrial semidiameters, ie., T. O. At T -with a radius of T.C. describe a circle. This will proportionally represent sun, earth, moon, and shadow, moon’s orbit between T and ■S. To a person at a distance of .a hundred miles from the earth a solar eclipse would be like a shadow passing across —indeed we see the dark shadow of clouds on land or sea very similar. Eclipses of sun and moon occur •of course one in ia day, the other at night, and should one occur fourteen days later, the other is very likely to take place. Eclipses of the sun can only occur at new moon —eclipses of the moon at full moon. The moon is the most extraordinary heavenly body we see, as -well as the nearest to us, because there is one half of her no inhabitant of the earth has ever seen, while people on her would see the earth four times as Idrge as she appears to us revolving in each 24 hours. It appears, therefore, she has something to hide from ns.' People with lively imaginations fancy she is a place of punishment where ’ unfortunates are scorched and 1 frozen alternately, as her day and •night last for a fortnight. Were the

sun riot to set for two weeks and not to rise for the next, it may easily be imagined what intense heat and cold would result, and the only way to avoid it would be to keep constantly travelling.

A transit of Mercury occurs on Nov. 11th. It commences at 3.16 a.m., and ends at 8.55 a.m. Sun rises Invercargill 4‘43 a.m. Mercury has just entered the sun at Greenwich when setting (at 4.15 p.m. Greenwich time) and 57 minutes after setting at Greenwich he rises at Invercargill. The dotted line shows the part of the transit the Invercargillites will miss. Transits of Mercury cannot be seen by the naked eye, the planet being too small. During the last transit (Sunday, May 10—91) a sun spot was to be seen, double yhe size of the planet. The first transit of Mercury was noted at Paris on Nov. 7th, 1631, the second in 1651. These were not seen by a telescope, but by making a slit in a dark chamber, so as to have the image of the sun formed on the opposite side. Photography is done in exactly the same way. A camera obscura means simply camera, chamber ; obscura, dark. Transits of Mercury and Venus bave been observed —

Transits of Mercury occur about once in nine years. Transits of Venus: Two having occurred in a space of eight years do not occur again until after 122 years. No one born since 1880 will see one.

The first Transit of Venus was calculated by Horrocks, a young* clergyman at Liverpool. He got greatly excited when he observed it. Venus can easily be seen on the sun Avithout a glass, as I can bear Avitness, having seen the Transit in 1882 in ISTorth America. Nothing, of course, but an internal planet can be seen crossing the sun. The Moon, Venus, and Mercury only do so. The nearer a planet is to its larger companion the more rapid is the movement round it. Anyone can illustrate this natural law by fixing a stone to a piece of string, SAvinging it round in a circle, and allowing it to Avind on the finger. As the stone approaches the finger the diameter of the circle becomes smaller, and its rapidity increases enormously. A long and short pendulum clock ticks slow or rapid in the same Avay, and shortening the pendulum makes the clock gain. The nearer Ave approach the centre of the earth the heavier we Avould weigh,and the higher we ascend a mountain the less. Suppose a loaf of bread weighed 41b at the bottom of the deepest mine, it Avould be far short of it at the top of the highest mountain. So a pendulum clock at the bottom of a mine keeping accurate time Avould lose rapidly if transferred to a mountain top. If a hole Avere drilled through the centre of the earth and a half hundredweight throAvn in, it would not come out at the other end, and for this reason: — The moon moA r es round us in her orbit very rapidly. The earth goes 16 miles a second. But she runs round the earth in each 28 days, and if anything suddenly stopped this motion of hers round ns, she Avould strike us this day week. Should the earth cease to round the sun, in 64 days we Avould strike the sun. But no living being Avould feel that shock. The first feAA r days Avould make the people shift into the lightest of summer clothing, and get tinted glasses to avoid the great light. Stores of proAusions would be loAA'ercd into deep mines, and steamers chartered for the North Pole, which would be easily reached, and if it happened to be winter in the northern hemisphere, no doubt the last man A\*ould be there. The sun would get larger until part of him AA’ould be setting, AA r hile the rest Avas'rising. We can imagine the last man, according to Campbell, addressing his destroyer — “Go, sun! Avhile mercy holds me up On nature’s aAvful waste To drink this last and bitter cup Of grief that man shall taste— Go! tell the night that hides thy face Thou saw’st the last of Adam’s race On earth’s sepulchral clod The darkening universe defy To quench his immortality. Or shake his trust in God.” The atyful magnitude of space and time confound the mind and give the first conceptions of eternity. The sphere and the circle haAm no beginning or end. It takes the pole 25,000 years to perform one act of nutation, Avhich the urchin’s giddy top does perhaps at the rate of 100 in a second. Returning to Meicury, an observer there would see the sun 6‘67 times larger than Ave see it, and of course it would increase heat and light in the same Avay. NarroAv-minded people at once conclude —“ He is uninhabited,” forgetting the Bible story of the burning, fiery furnace (Daniel 3)—probably meant to show that happiness is only the smile of the Creator. Naturally we ask —“ Are all these shining A\ ; orlds made for us, or wefor them ? ” We come here to learn something. Where we came from, or Avhere we go to, who can say ? But the moment consciousness

ceases, the body begins to decay. Hence we conclude—•“ The body is & house for the soul.” How the vegetable creation and lower animals are not capable of learning, but, according to Darwin and others, a kind of elevation of species called evolution is the design of nature. Nature has ordained all “ to become perfect by suffering.” This is the sum total of the Bible. The future, as shown in Revelation, is a mass of “ wars and rumours of wars.” It has been observed that, pleasure cannot be produced without causing pain. Even our games are mimic warfare, and yet we feel certain the Creator can have no pleasure in the sufferings of nature.

Mercury. November 7th, 1631 1651 1661 1667 November 11th, 1690 39 3rd, 1697 May 6th, 1707 November 9th, 1723 53 11th, 1736 May 2nd, 1740 November 5th, 1743 May 6 th, 1753 November 6 th, 1756 10th, 1769 12th, 1782 May 4th, 1786 November 5th, 1789 May 7th, 1799 November 9th, 1802 May 5th, 1832 8 th, 1845 November 8th, 1848 11th, 1861 4th, 1868 May 6th, 1878 November 7th, 1881 May 9th, 1891 To Come : Novembei’ 11th, 1894 33 4 th, 1901

Venus. December 4th, 1639 Jane 5 th, 1761 3rd, 1769 December 8th, 1874 99 6 th, 1882 June 7 th, 2004 99 5 th, 2012 December 10th, 2017 99 June 8 th, 2125 11th, 2247 8 th, 2255 December 12th, 2360 99 10th, 2368