Great Astronomers, Robert Stawell Ball [fox in socks read aloud txt] 📗

upon. The king made a grant

of five hundred pounds of money. He gave bricks from Tilbury

Fort, while materials, in the shape of wood, iron, and lead, were

available from a gatehouse demolished in the Tower. The king also

promised whatever further material aid might be shown to be

necessary. The first stone of the Royal Observatory was laid on

August 10th, 1675, and within a few years a building was erected

in which the art of modern practical astronomy was to be created.

Flamsteed strove with extraordinary diligence, and in spite of

many difficulties, to obtain a due provision of astronomical

instruments, and to arrange for the carrying on of his

observations. Notwithstanding the king’s promises, the astronomer

was, however, but scantily provided with means, and he had no

assistants to help him in his work. It follows that all the

observations, as well as the reductions, and, indeed, all the

incidental work of the observatory, had to be carried on by

himself alone. Flamsteed, as we have seen, had, however, many

staunch friends. Sir Jonas Moore in particular at all times

rendered him most valuable assistance, and encouraged him by the

warm sympathy and keen interest which he showed in astronomy. The

work of the first Astronomer Royal was frequently interrupted by

recurrent attacks of the complaints to which we have already

referred. He says himself that “his distempers stick so close

that that he cannot remove them,” and he lost much time by

prostration from headaches, as well as from more serious

affections.

 

The year 1678 found him in the full tide of work in his

observatory. He was specially engaged on the problem of the

earth’s motion, which he sought to derive from observations of the

sun and of Venus. But this, as well as many other astronomical

researches which he undertook, were only subsidiary to that which

he made the main task of his life, namely, the formation of a

catalogue of fixed stars. At the time when Flamsteed commenced

his career, the only available catalogue of fixed stars was that

of Tycho Brahe. This work had been published at the commencement

of the seventeenth century, and it contained about a thousand

stars. The positions assigned to these stars, though obtained

with wonderful skill, considering the many difficulties under

which Tycho laboured, were quite inaccurate when judged by our

modern standards. Tycho’s instruments were necessarily most

rudely divided, and he had, of course, no telescopes to aid him.

Consequently it was merely by a process of sighting that he could

obtain the places of the stars. It must further be remembered

that Tycho had no clocks, and no micrometers. He had, indeed, but

little correct knowledge of the motions of the heavenly bodies to

guide him. To determine the longitudes of a few principal stars

he conceived the ingenious idea of measuring by day the position

of Venus with respect to the sun, an observation which the

exceptional brightness of this planet rendered possible without

telescopic aid, and then by night he observed the position of

Venus with regard to the stars.

 

It has been well remarked by Mr. Baily, in his introduction

to the “British Catalogue of Stars,” that “Flamsteed’s

observations, by a fortunate combination of circumstances,

commenced a new and a brilliant era. It happened that, at that

period, the powerful mind of Newton was directed to this subject;

a friendly intercourse then existed between these two

distinguished characters; and thus the first observations that

could lay any claim to accuracy were at once brought in aid of

those deep researches in which our illustrious geometer was then

engaged. The first edition of the `Principia’ bears testimony to

the assistance afforded by Flamsteed to Newton in these inquiries;

although the former considers that the acknowledgment is not so

ample as it ought to have been.”

 

Although Flamsteed’s observations can hardly be said to possess

the accuracy of those made in more recent times, when instruments

so much superior to his have been available, yet they possess

an interest of a special kind from their very antiquity. This

circumstance renders them of particular importance to the

astronomer, inasmuch as they are calculated to throw light on the

proper motions of the stars. Flamsteed’s work may, indeed, be

regarded as the origin of all subsequent catalogues, and the

nomenclature which he adopted, though in some respects it can

hardly be said to be very defensible, is, nevertheless, that which

has been adopted by all subsequent astronomers. There were also a

great many errors, as might be expected in a work of such extent,

composed almost entirely of numerical detail. Many of these

errors have been corrected by Baily himself, the assiduous editor

of “Flamsteed’s Life and Works,” for Flamsteed was so harassed

from various causes in the latter part of his life, and was so

subject to infirmities all through his career, that he was unable

to revise his computations with the care that would have been

necessary. Indeed, he observed many additional stars which he

never included in the British Catalogue. It is, as Baily well

remarks, “rather a matter of astonishment that he accomplished so

much, considering his slender means, his weak frame, and the

vexations which he constantly experienced.”

 

Flamsteed had the misfortune, in the latter part of his life, to

become estranged from his most eminent scientific contemporaries.

He had supplied Newton with places of the moon, at the urgent

solicitation of the author of the “Principia,” in order that the

lunar theory should be carefully compared with observation. But

Flamsteed appears to have thought that in Newton’s further request

for similar information, he appeared to be demanding as a right

that which Flamsteed considered he was only called upon to render

as a favour. A considerable dispute grew out of this matter, and

there are many letters and documents, bearing on the difficulties

which subsequently arose, that are not, perhaps, very creditable

to either party.

 

Notwithstanding his feeble constitution, Flamsteed lived to the

age of seventy-three, his death occurring on the last day of the

year 1719.

 

HALLEY.

 

Isaac Newton was just fourteen years of age when the birth of

Edmund Halley, who was destined in after years to become Newton’s

warmly attached friend, and one of his most illustrious scientific

contemporaries, took place. There can be little doubt that the

fame as an astronomer which Halley ultimately acquired, great as

it certainly was, would have been even greater still had it not

been somewhat impaired by the misfortune that he had to shine in

the same sky as that which was illumined by the unparalleled

genius of Newton.

 

Edmund Halley was born at Haggerston, in the Parish of

St. Leonard’s, Shoreditch, on October 29th, 1656. His father, who

bore the same name as his famous son, was a soap-boiler in

Winchester Street, London, and he had conducted his business with

such success that he accumulated an ample fortune. I have been

unable to obtain more than a very few particulars with respect to

the early life of the future astronomer. It would, however,

appear that from boyhood he showed considerable aptitude for the

acquisition of various kinds of learning, and he also had some

capacity for mechanical invention. Halley seems to have received

a sound education at St. Paul’s School, then under the care of

Dr. Thomas Gale.

 

Here, the young philosopher rapidly distanced his competitors in

the various branches of ordinary school instruction. His

superiority was, however, most conspicuous in mathematical

studies, and, as a natural development of such tastes, we learn

that by the time he had left school he had already made good

progress in astronomy. At the age of seventeen he was entered as

a commoner at Queen’s College, Oxford, and the reputation that he

brought with him to the University may be inferred from the remark

of the writer of “Athenae Oxonienses,” that Halley came to Oxford

with skill in Latin, Greek, and Hebrew, and such a knowledge of

geometry as to make a complete dial.” Though his studies were

thus of a somewhat multifarious nature, yet it is plain that from

the first his most favourite pursuit was astronomy. His earliest

efforts in practical observation were connected with an eclipse

which he observed from his father’s house in Winchester Street.

It also appears that he had studied theoretical branches of

astronomy so far as to be conversant with the application of

mathematics to somewhat abstruse problems.

 

Up to the time of Kepler, philosophers had assumed almost as an

axiom that the heavenly bodies must revolve in circles and that

the motion of the planet around the orbit which it described must

be uniform. We have already seen how that great philosopher,

after very persevering labour, succeeded in proving that the

orbits of the planets were not circles, but that they were

ellipses of small eccentricity. Kepler was, however, unable to

shake himself free from the prevailing notion that the angular

motion of the planet ought to be of a uniform character around

some point. He had indeed proved that the motion round the focus

of the ellipse in which the sun lies is not of this description.

One of his most important discoveries even related to the fact

that at some parts of its orbit a planet swings around the sun

with greater angular velocity than at others. But it so happens

that in elliptic tracks which differ but little from circles, as

is the case with all the more important planetary orbits, the

motion round the empty focus of the ellipse is very nearly

uniform. It seemed natural to assume, that this was exactly the

case, in which event each of the two foci of the ellipse would

have had a special significance in relation to the movement of the

planet. The youthful Halley, however, demonstrated that so far as

the empty focus was concerned, the movement of the planet around

it, though so nearly uniform, was still not exactly so, and at the

age of nineteen, he published a treatise on the subject which at

once placed him in the foremost rank amongst theoretical

astronomers.

 

But Halley had no intention of being merely an astronomer with his

pen. He longed to engage in the practical work of observing. He

saw that the progress of exact astronomy must depend largely on

the determination of the positions of the stars with all

attainable accuracy. He accordingly determined to take up this

branch of work, which had been so successfully initiated by Tycho

Brahe.

 

At the present day, astronomers of the great national

observatories are assiduously engaged in the determination of the

places of the stars. A knowledge of the exact positions of these

bodies is indeed of the most fundamental importance, not alone

for the purposes of scientific astronomy, but also for navigation

and for extensive operations of surveying in which accuracy is

desired. The fact that Halley determined to concentrate himself

on this work shows clearly the scientific acumen of the young

astronomer.

 

Halley, however, found that Hevelius, at Dantzig, and Flamsteed,

the Astronomer Royal at Greenwich, were both engaged on

work of this character. He accordingly determined to direct his

energies in a way that he thought would be more useful to

science. He resigned to the two astronomers whom I have named the

investigation of the stars in the northern hemisphere, and he

sought for himself a field hitherto almost entirely unworked. He

determined to go to the southern hemisphere, there to measure and

survey those stars which were invisible in Europe, so that his

work should supplement the labours of the northern astronomers,

and that the joint result of his labours and of theirs might be a

complete survey of the most important stars on the surface of the

heavens.

 

In these days, after so many ardent students everywhere have

devoted themselves to the study