Astronomical Curiosities Part 22

A dark shade was seen on the waning moon by Messrs. Hirst and J. C.

Russell on October 21, 1878, "as dark as the shadow during an eclipse of the moon."[479] If this observation is correct, it is certainly most difficult to explain. Another curious observation is recorded by Mr. E.

Stone Wiggins, who says that a partial eclipse of the sun by a dark body was observed in the State of Michigan (U.S.A.) on May 16, 1884, at 7 p.m.

The "moon at that moment was 12 degrees south of the equator and the sun as many degrees north of it." The existence of a dark satellite of the earth has been suggested, but this seems highly improbable.

The sun's corona seems to have been first noticed in the total eclipse of the sun which occurred at the death of the Roman emperor Domitian, A.D.

95. Philostratus in his _Life of Apollonius_ says, with reference to this eclipse, "In the heavens there appeared a prodigy of this nature: a certain _corona_ resembling the Iris surrounded the orb of the sun, and obscured its light."[480] In more modern times the corona seems to have been first noticed by Clavius during the total eclipse of April 9, 1567.[481] Kepler proved that this eclipse was total, not annular, so that the ring seen by Clavius must have been the corona.

With reference to the visibility of planets and stars during total eclipses of the sun; in the eclipse of May 12, 1706, Venus, Mercury, and Aldebaran, and several other stars were seen. During the totality of the eclipse of May 3, 1715, about twenty stars were seen with the naked eye.[482] At the eclipse of May 22, 1724, Venus and Mercury, and a few fixed stars were seen.[483] The corona was also noticed. At the eclipse of May 2, 1733, Jupiter, the stars of the "Plough," Capella, and other stars were visible to the naked eye; and the corona was again seen.[483]

During the total eclipses of February 9, 1766, June 24, 1778, and June 16, 1806, the corona was again noticed. But its true character was then unknown.

At the eclipse of July 8, 1842, it was noticed by observers at Lipesk that the stars Aldebaran and Betelgeuse (a Orionis), which are usually red, "appeared quite white."[484]

There will be seven eclipses in the years 1917, 1935, and 1985. In the year 1935 there will be five eclipses of the sun, a rare event; and in 1985 there will be three total eclipses of the moon, a most unusual occurrence.[485]

Among the ancient Hindoos, the common people believed that eclipses were caused by the interposition of a monstrous demon called Raha. This absurd idea, and others equally ridiculous, were based on declarations in their sacred books, and no pious Hindoo would think of denying it.

The following cases of darkenings of the sun are given by Humboldt:--

According to Plutarch the sun remained pale for a whole year at the death of Julius Caesar, and gave less than its usual heat.[486]

A sun-darkening lasting for two hours is recorded on August 22, 358 A.D., before the great earthquake of Nicomedia.

In 360 A.D. there was a sun-darkening from early morn till noon. The description given by the historians of the time corresponds to an eclipse of the sun, but the duration of the obscurity is inexplicable.

In 409 A.D., when Alaric lay siege to Rome, "there was so great a darkness that the stars were seen by day."

In 536 A.D. the sun is said to have been darkened for a year and two months!

In 626 A.D., according to Abul Farag, half the sun's disc was darkened for eight months!

In 934 A.D. the sun lost its brightness for two months in Portugal.

In 1090 A.D. the sun was darkened for three hours.

In 1096, sun-spots were seen with the naked eye on March 3.

In 1206 A.D. on the last day of February, "there was complete darkness for six hours, turning the day into night." This seems to have occurred in Spain.

In 1241 the sun was so darkened that stars could be seen at 3 p.m. on Michaelmas day. This happened in Vienna.[487]

The sun is said to have been so darkened in the year 1547 A.D. for three days that stars were visible at midday. This occurred about the time of the battle of Muhlbergh.[488]

Some of these darkenings may possibly have been due to an enormous development of sun-spots; but in some cases the darkness is supposed by Chladni and Schnurrer to have been caused by "the pa.s.sage of meteoric ma.s.ses before the sun's disc."

The first observer of a transit of Venus was Jeremiah Horrocks, who observed the transit of November 24 (O.S.), 1639. He had previously corrected Kepler's predicted time of the transit from 8{h} 8{m} a.m. at Manchester to 5{h} 57{m} p.m. At the end of 1875 a marble scroll was placed on the pedestal of the monument of John Conduitt (nephew of Sir Isaac Newton, and who adopted Horrocks' theory of lunar motions) at the west end of the nave of Westminster Abbey, bearing this inscription from the pen of Dean Stanley--

"Ad majora avocatus quae ob haec parerga negligi non decuit"

IN MEMORY OF JEREMIAH HORROCKS Curate of Hoole in Lancas.h.i.+re Who died on the 3{d} of January, 1641, in or near his 22{d} year Having in so short a life Detected the long inequality in the mean motion of Jupiter and Saturn Discovered the orbit of the Moon to be an ellipse; Determined the motion of the lunar aspe, Suggested the physical cause of its revolution; And predicted from his own observations, the Transit of Venus Which was seen by himself and his friend WILLIAM CRABTREE On Sunday, the 24th November (O.S.) 1639; This Tablet, facing the Monument of Newton Was raised after the lapse of more than two centuries December 9, 1874.[489]

The transit of Venus which occurred in 1761 was observed on board s.h.i.+p(!) by the famous but unfortunate French astronomer Le Gentil. The s.h.i.+p was the frigate _Sylphide_, sent to the help of Pondicherry (India) which was then being besieged by the English. Owing to unfavourable winds the _Sylphide_ was tossed about from March 25, 1761, to May 24 of the same year. When, on the later date, off the coast of Malabar, the captain of the frigate learned that Pondicherry had been captured by the English, the vessel returned to the Isle of France, where it arrived on June 23, after touching at Point de Galle on May 30. It was between these two places that Le Gentil made his observations of the transit of Venus under such unfavourable conditions. He had an object-gla.s.s of 15 feet (French) focus, and this he mounted in a tube formed of "four pine planks." This rough instrument was fixed to a small mast set up on the quarter-deck and worked by ropes. The observations made under such curious conditions, were not, as may be imagined, very satisfactory. As another transit was to take place on June 3, 1769, Le Gentil made the heroic resolution of remaining in the southern hemisphere to observe it! This determination was duly carried out, but his devotion to astronomy was not rewarded; for on the day of the long waited for transit the sky at Pondicherry (where he had gone to observe it) was clouded over during the whole phenomenon, "although for many days previous the sky had been cloudless." To add to his feeling of disappointment he heard that at Manilla, where he had been staying some time previously, the sky was quite clear, and two of his friends there had seen the transit without any difficulty.[490] Truly the unfortunate Le Gentil was a martyr to science.

The famous German astronomer Bessel once said "that a practical astronomer could make observations of value if he had only a cart-wheel and a gun barrel"; and Watson said that "the most important part of the instrument is the person at the small end."[491]

With reference to Father h.e.l.l's supposed forgery of his observations of the transit of Venus in 1769, and Littrow's criticism of some of the entries in h.e.l.l's ma.n.u.script being corrected with a different coloured ink, Professor Newcomb ascertained from Weiss that Littrow was colour blind, and could not distinguish between the colour of Aldebaran and the whitest star. Newcomb adds, "For half a century the astronomical world had based an impression on the innocent but mistaken evidence of a colour-blind man respecting the tint of ink in a ma.n.u.script."

It is recorded that on February 26, B.C. 2012, the moon, Mercury, Venus, Jupiter, and Saturn, were in the same constellation, and within 14 degrees of each other. On September 14, 1186 A.D., the sun, moon, and all the planets then known, are said to have been situated in Libra.[492]

In the Sanscrit epic poem, "The Ramaya," it is stated that at the birth of Rama, the moon was in Cancer, the sun in Aries, Mercury in Taurus, Venus in Pisces, Mars in Capricornus, Jupiter in Cancer, and Saturn in Libra.

From these data, Mr. Walter R. Old has computed that Rama was born on February 10, 1761 B.C.[493]

A close conjunction of Mars and Saturn was observed by Denning on September 29, 1889, the bright star Regulus (a Leonis) being at the time only 47' distant from the planets.[494]

An occultation of the Pleiades by the moon was observed by Timocharis at Alexandria on January 29, 282 B.C. Calculations by Schjellerup show that Alcyone (? Tauri) was occulted; but the exact time of the day recorded by Timocharis differs very considerably from that computed by Schjellerup.[495] Another occultation of the Pleiades is recorded by Agrippa in the reign of Domitian. According to Schjellerup the phenomenon occurred on November 29, A.D. 92.

"Kepler states that on the 9th of January, 1591, Maestlin and himself witnessed an occultation of Jupiter by Mars. The red colour of the latter on that occasion plainly indicated that it was the inferior planet."[496]

That is, that Mars was nearer to the sun than Jupiter. But as the telescope had not then been invented, this may have been merely a near approach of the two planets.

According to Kepler, Maestlin saw an occultation of Mars by Venus on October 3, 1590. But this may also have been merely a near approach.[496]

A curious paradox is that one can discover an object without seeing it, and see an object without discovering it! The planet Neptune was discovered by Adams and Leverrier by calculation before it was seen in the telescope by Galle; and it was actually seen by Lalande on May 8 and 10, 1795, but he took it for a _star_ and thus missed the discovery. In fact, he _saw_ the planet, but did not _discover_ it. It actually appears as a star of the 8th magnitude in Harding's Atlas (1822). The great "new star"

of February, 1901, known as Nova Persei, was probably seen by some people before its discovery was announced; and it was actually noticed by a well-known American astronomer, who thought it was some bright star with which he was not familiar! But this did not amount to a discovery. Any one absolutely ignorant of astronomy might have made the same observation. An object must be _identified_ as a _new_ object before a discovery can be claimed. Some years ago a well-known Irish naturalist discovered a spider new to science, and after its discovery he found that it was common in nearly every house in Dublin! But this fact did not detract in the least from the merit of its scientific discovery.

There is a story of an eminent astronomer who had been on several eclipse expeditions, and yet was heard to remark that he had never seen a total eclipse of the sun. "But your observations of several eclipses are on record," it was objected. "Certainly, I have on several occasions made observations, but I have always been too busy to look at the eclipse." He was probably in a dark tent taking photographs or using a spectroscope during the totality. This was observing an eclipse without seeing it!

Humboldt gives the credit of the invention of the telescope to Hans Lippershey, a native of Wesel and a spectacle-maker at Middleburgh; to Jacob Adreaansz, surnamed Metius, who is also said to have made burning-gla.s.ses of ice; and to Zachariah Jansen.[497]

With reference to the parabolic figure of the large mirrors of reflecting telescopes, Dr. Robinson remarked at the meeting of the British a.s.sociation at Cork in 1843, "between the spherical and parabolic figures the extreme difference is so slight, even in the telescope of 6-feet aperture [Lord Rosse's] that if the two surfaces touched at their vertex, the distance at the edge would not amount to the 1/10000th of an inch, a s.p.a.ce which few can measure, and none without a microscope."[498]

In the year 1758, Roger Long, Lowndean Professor of Astronomy at Cambridge, constructed an "orrery" on a novel principle. It was a hollow metal sphere of about 18 feet in diameter with its fixed axis parallel to the earth's axis. It was rotated, by means of a winch and rackwork. It held about thirty persons in its interior, where astronomical lectures were delivered. The constellations were painted on the interior surface; and holes pierced through the sh.e.l.l and illuminated from the outside represented the stars according to their different magnitudes. This ingenious machine was much neglected for many years, but was still in existence in Admiral Smyth's time, 1844.[499]

A "temporary star" is said to have been seen by Hepida.n.u.s in the constellation Aries in either 1006 or 1012 A.D. The late M. Schonfeld, a great authority on variable stars, found from an Arabic and Syrian chronicle that 1012 is the correct year (396 of the Hegira), but that the word translated Aries would by a probable emendation mean Scorpio. The word in the Syrian record is not the word for Aries.[500]

Mr. Heber D. Curtis finds that the faintest stars mentioned in Ptolemy's Catalogue are about 538 magnitude on the scale of the Harvard _Photometric Durchmustering_.[501] Heis and Houzeau saw stars of 6-7 magnitude (about 64 on Harvard scale). The present writer found that he could see most of Heis' faintest stars in the west of Ireland (Co. Sligo) without optical aid (except short-sighted spectacles).

With reference to the apparent changes in the stellar heavens produced by the precession of the equinoxes, Humboldt says--

"Canopus was fully 1 20' below the horizon of Toledo (39 54' north lat.i.tude) in the time of Columbus; and now the same star is almost as much above the horizon of Cadiz. While at Berlin, and in northern lat.i.tudes, the stars of the Southern Cross, as well as a and Centauri, are receding more and more from view, the Magellanic Clouds are slowly approaching our lat.i.tudes. Canopus was at its greatest northern approximation during last century [eighteenth], and is now moving nearer and nearer to the south, although very slowly, owing to its vicinity to the south pole of the ecliptic. The Southern Cross began to become invisible in 52 30' north lat.i.tude 2900 years before our era, since, according to Galle, this constellation might previously have reached an alt.i.tude of more than 10. When it had disappeared from the horizon of the countries of the Baltic, the great pyramid of Cheops had already been erected more than five hundred years. The pastoral tribe of the Hyksos made their incursion seven hundred years earlier. The past seems to be visibly nearer to us when we connect its measurement with great and memorable events."[502]

With reference to the great Grecian philosopher and scientist Eratosthenes of Cyrene, keeper of the Alexandrian Library under Ptolemy Euergetes, Carl Snyder says, "Above all the Alexanders, Caesars, Tadema-Napoleons, I set the brain which first spanned the earth, over whose little patches these fought through their empty bootless lives. Why should we have no poet to celebrate so great a deed?"[503] And with reference to Aristarchus he says, "If grandeur of conceptions be a measure of the brain, or ingenuity of its powers, then we must rank Aristarchus as one of the three or four most acute intellects of the ancient world."[504]

Lagrange, who often a.s.serted Newton to be the greatest genius that ever existed, used to remark also--"and the most fortunate; we do not find more than once a system of the world to establish."[505]

Grant says--

"Lagrange deserves to be ranked among the greatest mathematical geniuses of ancient or modern times. In this respect he is worthy of a place with Archimedes or Newton, although he was far from possessing the sagacity in physical enquiries which distinguished these ill.u.s.trious sages. From the very outset of his career he a.s.sumed a commanding position among the mathematicians of the age, and during the course of nearly half a century previous to his death, he continued to divide with Laplace the homage due to pre-eminence in the exact sciences. His great rival survived him fourteen years, during which he reigned alone as the prince of mathematicians and theoretical astronomers."[506]

A writer in _Nature_ (May 25, 1871) relates the following anecdote with reference to Sir John Herschel: "Some time after the death of Laplace, the writer of this notice, while travelling on the continent in company with the celebrated French _savant_ Biot, ventured to put to him the question, not altogether a wise one, 'And whom of all the philosophers of Europe do you regard as the most worthy successor of Laplace?' Probably no man was better able than Biot to form a correct conclusion, and the reply was more judicious than the question. It was this, 'If I did not love him so much I should unhesitatingly say, Sir John Herschel.'" Dr. Gill (now Sir David Gill), in an address at the Cape of Good Hope in June, 1898, spoke of Sir John Herschel as "the prose poet of science; his popular scientific works are models of clearness, and his presidential addresses teem with pa.s.sages of surpa.s.sing beauty. His life was a pure and blameless one from first to last, full of the n.o.blest effort and the n.o.blest aim from the time when as a young Cambridge graduate he registered a vow 'to try to leave the world wiser than he found it'--a vow that his life amply fulfilled."[507]