Great Astronomers by Robert Stawell Ball (best ereader for students .txt) 📖

instruments. After a voyage of two months, which was

considered to be a fair passage in those days, he landed in Table

Bay, and having duly reconnoitred various localities, he decided

to place his observatory at a place called Feldhausen, about six

miles from Cape Town, near the base of the Table Mountain. A

commodious residence was there available, and in it he settled

with his family. A temporary building was erected to contain the

equatorial, but the great twenty-foot telescope was accommodated

with no more shelter than is provided by the open canopy of

heaven.

 

As in his earlier researches at home, the attention of the great

astronomer at the Cape of Good Hope was chiefly directed to the

measurement of the relative positions and distances apart of the

double stars, and to the close examination of the nebulae. In the

delineation of the form of these latter objects Herschel found

ample employment for his skilful pencil. Many of the drawings he

has made of the celestial wonders in the southern sky are

admirable examples of celestial portraiture.

 

The number of the nebulae and of those kindred objects, the star

clusters, which Herschel studied in the southern heavens, during

four years of delightful labour, amount in all to one thousand

seven hundred and seven. His notes on their appearance, and the

determinations of their positions, as well as his measurements of

double stars, and much other valuable astronomical research, were

published in a splendid volume, brought out at the cost of the

Duke of Northumberland. This is, indeed, a monumental work, full

of interesting and instructive reading for any one who has a

taste for astronomy.

 

Herschel had the good fortune to be at the Cape on the occasion of

the periodical return of Halley’s great comet in 1833. To the

study of this body he gave assiduous attention, and the records of

his observations form one of the most interesting chapters in that

remarkable volume to which we have just referred.

 

[PLATE: COLUMN AT FELDHAUSEN, CAPE TOWN, to commemorate Sir John

Herschel’s survey of the Southern Heavens.]

 

Early in 1838 Sir John Herschel returned to England. He had made

many friends at the Cape, who deeply sympathised with his self-imposed labours while he was resident among them. They desired to

preserve the recollection of this visit, which would always, they

considered, be a source of gratification in the colony.

Accordingly, a number of scientific friends in that part of the

world raised a monument with a suitable inscription, on the

spot which had been occupied by the great twenty-foot reflector at

Feldhausen.

 

His return to England after five years of absence was naturally

an occasion for much rejoicing among the lovers of astronomy. He

was entertained at a memorable banquet, and the Queen, at her

coronation, made him a baronet. His famous aunt Caroline, at that

time aged eighty, was still in the enjoyment of her faculties, and

was able to estimate at its true value the further

lustre which was added to the name she bore. But there is reason

to believe that her satisfaction was not quite unmixed with

other feelings. With whatever favour she might regard her nephew,

he was still not the brother to whom her life had been devoted.

So jealous was this vigorous old lady of the fame of the great

brother William, that she could hardly hear with patience of the

achievements of any other astronomer, and this failing existed in

some degree even when that other astronomer happened to be her

illustrious nephew.

 

With Sir John Herschel’s survey of the Southern Hemisphere it may

be said that his career as an observing astronomer came to a close.

He did not again engage in any systematic telescopic research.

But it must not be inferred from this statement that he desisted

from active astronomical work. It has been well observed that Sir

John Herschel was perhaps the only astronomer who has studied with

success, and advanced by original research, every department of

the great science with which his name is associated. It was to

some other branches of astronomy besides those concerned with

looking through telescopes, that the rest of the astronomer’s life

was to be devoted.

 

To the general student Sir John Herschel is best known by the

volume which he published under the title of “Outlines of

Astronomy.” This is, indeed, a masterly work, in which the

characteristic difficulties of the subject are resolutely faced

and expounded with as much simplicity as their nature will admit.

As a literary effort this work is admirable, both on account of

its picturesque language and the ennobling conceptions of the

universe which it unfolds. The student who desires to become

acquainted with those recondite departments of astronomy, in which

the effects of the disturbing action of one planet upon the

motions of another planet are considered, will turn to the

chapters in Herschel’s famous work on the subject. There he will

find this complex matter elucidated, without resort to difficult

mathematics. Edition after edition of this valuable work has

appeared, and though the advances of modern astronomy have left it

somewhat out of date in certain departments, yet the expositions

it contains of the fundamental parts of the science still remain

unrivalled.

 

Another great work which Sir John undertook after his return from

the Cape, was a natural climax to those labours on which his

father and he had been occupied for so many years. We have

already explained how the work of both these observers had been

mainly devoted to the study of the nebulae and the star clusters.

The results of their discoveries had been announced to the world

in numerous isolated memoirs. The disjointed nature of these

publications made their use very inconvenient. But still it was

necessary for those who desired to study the marvellous objects

discovered by the Herschels, to have frequent recourse to the

original works. To incorporate all the several observations of

nebular into one great systematic catalogue, seemed, therefore, to

be an indispensable condition of progress in this branch of

knowledge. No one could have been so fitted for this task as Sir

John Herschel. He, therefore, attacked and carried through the

great undertaking. Thus at last a grand catalogue of nebulae and

clusters was produced. Never before was there so majestic an

inventory. If we remember that each of the nebulae is an object

so vast, that the whole of the solar system would form an

inconsiderable speck by comparison, what are we to think of a

collection in which these objects are enumerated in thousands? In

this great catalogue we find arranged in systematic order all the

nebulae and all the clusters which had been revealed by the

diligence of the Herschels, father and son, in the Northern

Hemisphere, and of the son alone in the Southern Hemisphere. Nor

should we omit to mention that the labours of other astronomers

were likewise incorporated. It was unavoidable that the

descriptions given to each of the objects should be very slight.

Abbreviations are used, which indicate that a nebula is bright, or

very bright, or extremely bright, or faint, or very faint, or

extremely faint. Such phrases have certainly but a relative and

technical meaning in such a catalogue. The nebulae entered as

extremely bright by the experienced astronomer are only so

described by way of contrast to the great majority of these

delicate telescopic objects. Most of the nebulae, indeed, are so

difficult to see, that they admit of but very slight description.

It should be observed that Herschel’s catalogue augmented the

number of known nebulous objects to more than ten times that

collected into any catalogue which had ever been compiled before

the days of William Herschel’s observing began. But the study of

these objects still advances, and the great telescopes now in use

could probably show at least twice as many of these objects as are

contained in the list of Herschel, of which a new and enlarged

edition has since been brought out by Dr. Dreyer.

 

One of the best illustrations of Sir John Herschel’s literary

powers is to be found in the address which he delivered at the

Royal Astronomical Society, on the occasion of presenting a medal

to Mr. Francis Baily, in recognition of his catalogue of stars.

The passage I shall here cite places in its proper aspect the true

merit of the laborious duty involved in such a task as that which

Mr. Baily had carried through with such success:—

 

“If we ask to what end magnificent establishments are maintained

by states and sovereigns, furnished with masterpieces of art, and

placed under the direction of men of first-rate talent and high-minded enthusiasm, sought out for those qualities among the

foremost in the ranks of science, if we demand QUI BONO? for

what good a Bradley has toiled, or a Maskelyne or a Piazzi has

worn out his venerable age in watching, the answer is—not to

settle mere speculative points in the doctrine of the universe;

not to cater for the pride of man by refined inquiries into the

remoter mysteries of nature; not to trace the path of our system

through space, or its history through past and future eternities.

These, indeed, are noble ends and which I am far from any thought

of depreciating; the mind swells in their contemplation, and

attains in their pursuit an expansion and a hardihood which fit it

for the boldest enterprise. But the direct practical utility of

such labours is fully worthy of their speculative grandeur. The

stars are the landmarks of the universe; and, amidst the endless

and complicated fluctuations of our system, seem placed by its

Creator as guides and records, not merely to elevate our minds by

the contemplation of what is vast, but to teach us to direct our

actions by reference to what is immutable in His works. It is,

indeed, hardly possible to over-appreciate their value in this

point of view. Every well-determined star, from the moment its

place is registered, becomes to the astronomer, the geographer,

the navigator, the surveyor, a point of departure which can never

deceive or fail him, the same for ever and in all places, of a

delicacy so extreme as to be a test for every instrument yet

invented by man, yet equally adapted for the most ordinary

purposes; as available for regulating a town clock as for

conducting a navy to the Indies; as effective for mapping down the

intricacies of a petty barony as for adjusting the boundaries of

Transatlantic empires. When once its place has been thoroughly

ascertained and carefully recorded, the brazen circle with which

that useful work was done may moulder, the marble pillar may

totter on its base, and the astronomer himself survive only in the

gratitude of posterity; but the record remains, and transfuses

all its own exactness into every determination which takes it for

a groundwork, giving to inferior instruments—nay, even to

temporary contrivances, and to the observations of a few weeks or

days—all the precision attained originally at the cost of so much

time, labour, and expense.”

 

Sir John Herschel wrote many other works besides those we have

mentioned. His “Treatise on Meteorology” is, indeed, a standard

work on this subject, and numerous articles from the same pen on

miscellaneous subjects, which have been collected and reprinted,

seemed as a relaxation from his severe scientific studies. Like

certain other great mathematicians Herschel was also a poet, and

he published a translation of the Iliad into blank verse.

 

In his later years Sir John Herschel lived a retired life. For a

brief period he had, indeed, been induced to accept the office of

Master of the Mint. It was, however, evident that the routine of

such an occupation was not in accordance with his tastes, and he

gladly resigned it, to return to the seclusion of his