Great Astronomers - Robert Stawell Ball (the little red hen ebook .TXT) 📗

from any

one of the hundreds and thousands of stars which exist elsewhere

in space. Indeed, we may say at once that this little object was

not a star at all; it was a planet. That such was its true nature

was confirmed, after a little further observation, by perceiving

that the body was shifting its place on the heavens relatively to

the stars. The organist at the Octagon Chapel at Bath had,

therefore, discovered a new planet with his home-made telescope.

 

I can imagine some one will say, “Oh, there was nothing so

wonderful in that; are not planets always being discovered? Has

not M. Palisa, for instance discovered about eighty of such

objects, and are there not hundreds of them known nowadays?” This

is, to a certain extent, quite true. I have not the least desire

to detract from the credit of those industrious and sharp-sighted

astronomers who have in modern days brought so many of these

little objects within our cognisance. I think, however, it must

be admitted that such discoveries have a totally different

importance in the history of science from that which belongs to

the peerless achievement of Herschel. In the first place, it must

be observed that the minor planets now brought to light are so

minute that if a score of them were rolled to together into one

lump it would not be one-thousandth part of the size of the grand

planet discovered by Herschel. This is, nevertheless, not the

most important point. What marks Herschel’s achievement as one of

the great epochs in the history of astronomy is the fact that the

detection of Uranus was the very first recorded occasion of the

discovery of any planet whatever.

 

For uncounted ages those who watched the skies had been aware of

the existence of the five old planets-Jupiter, Mercury, Saturn,

Venus, and Mars. It never seems to have occurred to any of the

ancient philosophers that there could be other similar objects as

yet undetected over and above the well-known five. Great then was

the astonishment of the scientific world when the Bath organist

announced his discovery that the five planets which had been known

from all antiquity must now admit the company of a sixth. And

this sixth planet was, indeed, worthy on every ground to be

received into the ranks of the five glorious bodies of antiquity.

It was, no doubt, not so large as Saturn, it was certainly very

much less than Jupiter; on the other hand, the new body was very

much larger than Mercury, than Venus, or than Mars, and the earth

itself seemed quite an insignificant object in comparison with

this newly added member of the Solar System. In one respect, too,

Herschel’s new planet was a much more imposing object than any one

of the older bodies; it swept around the sun in a majestic orbit,

far outside that of Saturn, which had previously been regarded as

the boundary of the Solar System, and its stately progress

required a period of not less than eighty-one years.

 

King George the Third, hearing of the achievements of the

Hanoverian musician, felt much interest in his discovery, and

accordingly Herschel was bidden to come to Windsor, and to

bring with him the famous telescope, in order to exhibit the new

planet to the King, and to tell his Majesty all about it. The

result of the interview was to give Herschel the opportunity for

which he had so long wished, of being able to devote himself

exclusively to science for the rest of his life.

 

[PLATE: VIEW OF THE OBSERVATORY, HERSCHEL HOUSE, SLOUGH.]

 

The King took so great a fancy to the astronomer that he first, as

I have already mentioned, duly pardoned his desertion from the

army, some twenty-five years previously. As a further mark of his

favour the King proposed to confer on Herschel the title of his

Majesty’s own astronomer, to assign to him a residence near

Windsor, to provide him with a salary, and to furnish such funds

as might be required for the erection of great telescopes, and

for the conduct of that mighty scheme of celestial observation on

which Herschel was so eager to enter. Herschel’s capacity for

work would have been much impaired if he had been deprived of the

aid of his admirable sister, and to her, therefore, the King also

assigned a salary, and she was installed as Herschel’s assistant

in his new post.

 

With his usually impulsive determination, Herschel immediately cut

himself free from all his musical avocations at Bath, and at once

entered on the task of making and erecting the great telescopes at

Windsor. There, for more than thirty years, he and his faithful

sister prosecuted with unremitting ardour their nightly scrutiny

of the sky. Paper after paper was sent to the Royal Society,

describing the hundreds, indeed the thousands, of objects such as

double stars; nebulae and clusters, which were first revealed to

human gaze during those midnight vigils. To the end of his life

he still continued at every possible opportunity to devote himself

to that beloved pursuit in which he had such unparalleled success.

No single discovery of Herschel’s later years was, however, of the

same momentous description as that which first brought him to

fame.

 

[PLATE: THE 40-FOOT TELESCOPE AS IT WAS IN THE YEAR 1863,

HERSCHEL HOUSE, SLOUGH.]

 

Herschel married when considerably advanced in life and he lived

to enjoy the indescribable pleasure of finding that his only

son, afterwards Sir John Herschel, was treading worthily in his

footsteps, and attaining renown as an astronomical observer,

second only to that of his father. The elder Herschel died in

1822, and his illustrious sister Caroline then returned to

Hanover, where she lived for many years to receive the respect and

attention which were so justly hers. She died at a very advanced

age in 1848.

 

LAPLACE.

 

The author of the “Mecanique Celeste” was born at Beaumont-en-Auge, near Honfleur, in 1749, just thirteen years later than his

renowned friend Lagrange. His father was a farmer, but appears to

have been in a position to provide a good education for a son who

seemed promising. Considering the unorthodoxy in religious

matters which is generally said to have characterized Laplace in

later years, it is interesting to note that when he was a boy the

subject which first claimed his attention was theology. He was,

however, soon introduced to the study of mathematics, in which he

presently became so proficient, that while he was still no more

than eighteen years old, he obtained employment as a mathematical

teacher in his native town.

 

Desiring wider opportunities for study and for the acquisition of

fame than could be obtained in the narrow associations of

provincial life, young Laplace started for Paris, being provided

with letters of introduction to D’Alembert, who then occupied

the most prominent position as a mathematician in France, if not

in the whole of Europe. D’Alembert’s fame was indeed so

brilliant that Catherine the Great wrote to ask him to undertake

the education of her Son, and promised the splendid income of a

hundred thousand francs. He preferred, however, a quiet life of

research in Paris, although there was but a modest salary attached

to his office. The philosopher accordingly declined the alluring

offer to go to Russia, even though Catherine wrote again to say:

“I know that your refusal arises from your desire to cultivate

your studies and your friendships in quiet. But this is of no

consequence: bring all your friends with you, and I promise you

that both you and they shall have every accommodation in my

power.” With equal firmness the illustrious mathematician

resisted the manifold attractions with which Frederick the Great

sought to induce him, to take up his residence at Berlin. In

reading of these invitations we cannot but be struck at the

extraordinary respect which was then paid to scientific

distinction. It must be remembered that the discoveries of such

a man as D’Alembert were utterly incapable of being appreciated

except by those who possessed a high degree of mathematical

culture. We nevertheless find the potentates of Russia and

Prussia entreating and, as it happens, vainly entreating, the

most distinguished mathematician in France to accept the

positions that they were proud to offer him.

 

It was to D’Alembert, the profound mathematician, that young

Laplace, the son of the country farmer, presented his letters of

introduction. But those letters seem to have elicited no reply,

whereupon Laplace wrote to D’Alembert submitting a discussion on

some point in Dynamics. This letter instantly produced the

desired effect. D’Alembert thought that such mathematical talent

as the young man displayed was in itself the best of introductions

to his favour. It could not be overlooked, and accordingly he

invited Laplace to come and see him. Laplace, of course,

presented himself, and ere long D’Alembert obtained for the rising

philosopher a professorship of mathematics in the Military School

in Paris. This gave the brilliant young mathematician the opening

for which he sought, and he quickly availed himself of it.

 

Laplace was twenty-three years old when his first memoir on a

profound mathematical subject appeared in the Memoirs of the

Academy at Turin. From this time onwards we find him publishing

one memoir after another in which he attacks, and in many cases

successfully vanquishes, profound difficulties in the application

of the Newtonian theory of gravitation to the explanation of the

solar system. Like his great contemporary Lagrange, he loftily

attempted problems which demanded consummate analytical skill for

their solution. The attention of the scientific world thus became

riveted on the splendid discoveries which emanated from these two

men, each gifted with extraordinary genius.

 

Laplace’s most famous work is, of course, the “Mecanique

Celeste,” in which he essayed a comprehensive attempt to carry out

the principles which Newton had laid down, into much greater

detail than Newton had found practicable. The fact was that

Newton had not only to construct the theory of gravitation, but he

had to invent the mathematical tools, so to speak, by which his

theory could be applied to the explanation of the movements of the

heavenly bodies. In the course of the century which had elapsed

between the time of Newton and the time of Laplace, mathematics

had been extensively developed. In particular, that potent

instrument called the infinitesimal calculus, which Newton had

invented for the investigation of nature, had become so far

perfected that Laplace, when he attempted to unravel the movements

of the heavenly bodies, found himself provided with a calculus far

more efficient than that which had been available to Newton. The

purely geometrical methods which Newton employed, though they are

admirably adapted for demonstrating in a general way the

tendencies of forces and for explaining the more obvious phenomena

by which the movements of the heavenly bodies are disturbed, are

yet quite inadequate for dealing with the more subtle effects of

the Law of Gravitation. The disturbances which one planet

exercises upon the rest can only be fully ascertained by the aid

of long calculation, and for these calculations analytical methods

are required.

 

With an armament of mathematical methods which had been perfected

since the days of Newton by the labours of two or three

generations of consummate mathematical inventors, Laplace essayed

in the “Mecanique Celeste” to unravel the mysteries of the

heavens. It will hardly be disputed that the book which he has

produced is one of the most difficult books to understand that has

ever been written. In great part, of course, this difficulty

arises from the very nature of the subject, and is so far

unavoidable. No one need attempt to read the “Mecanique Celeste”

who has not been naturally endowed with considerable mathematical

aptitude which he has cultivated by years of assiduous study. The

critic will also note that there are grave defects in Laplace’s

method of