CHAPTER VIII.
PERSONALITY AND INFLUENCE.
Scientific biographies are sometimes painful reading—painful because in them we are occasionally brought face to face with the flaws in great characters, the pettinesses of great minds. The biography of Herschel does not belong to that class. The character which shines through his writings, through his sister's memoirs, and through the correspondence and comments of contemporaries is that of a genial, kindly, earnest man. In private life he was a good husband and father, a loving brother and a devoted son. His less fortunate relatives found in him a ready and willing helper: he maintained his brother Alexander after his retirement until his death in 1821. Even to Dieterich, the shiftless member of the family, he was unfailingly kind and sympathetic, bequeathing to him a sum of £2000. From earliest years he was to Caroline "the best and dearest of brothers," and that his care for her did not close with his death is evident from his bequest to her of an annuity. Alike in times of adversity and prosperity, he was ever helpful and kind.
He had none of that aloofness which has often characterized men of science. He was at all times ready to reply to correspondents and to answer inquiries. He was always accessible and never pedantic. The poet Campbell has given us a charming word-picture of the astronomer in private life. Writing to a friend on 15th September, 1813, Campbell said: "I wish you had been with me the day before yesterday, when you would have joined me, I am sure, deeply in admiring a great, simple, good old man—Dr. Herschel. . . . His simplicity, his kindness, his anecdotes, his readiness to explain—and make perfectly conspicuous too—his own sublime conceptions of the Universe, are indescribably charming. He is seventy-six, but fresh and stout, and there he sat nearest the door at his friend's house, alternately smiling at a joke, or contentedly sitting without share or notice in the conversation. Any train of conversation he follows implicitly; anything you ask he labours with a sort of boyish earnestness to explain. . . . Speaking of himself he said, with a modesty of manner which quite overcame me, when taken together with the greatness of the assertion, 'I have looked further into space than ever human being did before me. I have observed stars of which the light, it can be proved, must take two millions of years to reach this earth'."
Herschel's close friendships were few but enduring. Sir William Watson, Sir Joseph Banks, Dr. Maskelyne, and Mr. Aubert, were intimate friends and correspondents of many years' standing. Among continental astronomers, Lalande, Bode, and Schröter, were the most frequent correspondents. With men of science his relations were as harmonious as with humble amateurs or anxious inquirers. No acrimonious controversies disturbed the even tenor of his scientific career. The nearest approach to heat was in his paper of 1793, when he made his spirited refutation of Schröter's alleged discovery of high mountains in Venus; and on that occasion his words were probably written more in the spirit of banter than controversy. At least, Schröter seems to have so regarded them, for the two astronomers continued to be friendly correspondents.
His mind was many-sided, and to the end his interests were varied. His love for music never left him, nor did that early interest in metaphysical and logical reasoning which prompted the seventeen-year-old musician to spend all his earnings on a copy of Locke's "Essay on the Human Understanding". His early contributions to the Bath Literary Society included a number of philosophical papers. One of these dealt with the "utility of speculative inquiries". In this there occurs the following passage, which gives us some idea of the catholicity of his mind and also an insight into the secret of his success as a man of science: "It was said that speculation and metaphysics were of little use to mankind. This I deny. The perfection of our nature is evidently to be looked for in the superior powers of reason and speculation. What would all experiments avail if we should stop there and not argue upon them so as to draw general conclusions? And how can we argue and draw conclusions if the superior intellectual powers are not improved by frequent exercise in speculative researches? Half a dozen experiments made with judgment by a person who reasons well are worth a thousand random observations of insignificant matters of fact. But setting aside the very obvious consequences of improved faculties, the subjects of mere speculative knowledge are of the highest concern to those who love wisdom. By metaphysics we are enabled to prove the existence of a First Cause, the Infinite Author of all dependent beings. By mathematics we come to have a just idea of the superlative perfection of His works. By logic we can prove them to others. By ethics we are made sensible of our duty towards the Author of our existence and to our fellow-creatures."
This full-orbed conception of the world seems to have saved Herschel from falling under the influence of the spirit of scepticism then prevalent among men of science. In his mind—keen and logical as it was—there seems to have been no conflict between the scientific and religious instincts. In a letter to a correspondent, dated 1st January, 1794, he said, quite simply and without affectation: "It is certainly a very laudable thing to receive instruction from the great Workmaster of Nature, and for that reason all experimental philosophy is instituted".
In his paper on the "Construction of the Heavens," in 1785, he wrote, "We ought to avoid two opposite extremes. If we indulge a fanciful imagination and build worlds of our own, we must not wonder at our going wide from the path of truth and nature. . . . On the other hand, if we add observation to observation without attempting to draw not only certain conclusions but also conjectural views from them, we offend against the very end for which only observations ought to be made." This principle he maintained throughout his life. We can trace its operation through all the wonderful series of papers which he communicated to the Royal Society. In regard to the Milky Way, to island universes, to the nature of nebulæ, to double stars, to the Sun and planets, we see him collecting facts, framing hypotheses to account for these facts, and testing them by further facts. He had no fear of propounding theories, nor had he hesitation in withdrawing them. Theories were to him means to an end—the discovery of truth.
The career of Herschel marked an epoch in astronomy. His powerful genius directed the course of the science in the nineteenth century; and modern astronomy still bears the impress of his massive mind. When he began his long career as an observer, astronomy had become more or less a branch of applied mathematics. Such was not to be wondered at; the immediate task of the eighteenth century was the proof of the universal validity of the Newtonian law—a task carried forward to a triumphant conclusion by Lagrange and Laplace. But one result of the concentration of energy on the mathematical side of the science was that the study of the physical condition of the Sun, Moon, and planets was largely neglected; while the stellar branch of astronomy was virtually non-existent.
As a result of his development of the powers of the telescope, Herschel was enabled to take the whole field of observational astronomy for his province. He enormously extended knowledge of the Sun; and his solar theory, untenable though it proved, was the first attempt to systematise and co-ordinate the known facts concerning the Sun. His work on the various worlds of the Solar System marked the foundation of modern planetary topography. His paper on Mars in 1784 constituted Martian astronomy a distinct branch of the science. The scientific study of the Saturnian system may be said to have begun with him; he was the author of the first serious attempt to explain the atmospheric phenomena on Jupiter. He not only discovered Uranus—and thus prepared the way for the discovery of Neptune—but he persistently scrutinised its disc until he ascertained its size and mass. His discoveries of satellites did not exhaust his work on the secondary systems. His remarkable intuition that the rotation periods of satellites are equal to their times of revolution was one of the flashes of his genius.
In stellar astronomy he discovered binary stars, and thus proved what others had suspected—that the law of gravitation was of universal application. With consummate skill and audacity he attacked the highly difficult and elusive problem of the solar motion, and successfully measuring its rate and direction, he demonstrated further the essential kinship of Sun and stars. His efforts to know the construction of the heavens were unsuccessful, but he laid the foundation of a new branch of astronomy—that dealing with the distribution and motions of the stars; and in addition discovered suns and worlds in process of formation. Herschel was the first student of nature to point to evolution in progress and to classify natural objects in evolutionary array.
Above all, Herschel enormously widened the mental horizon of man. His researches extended the universe both in space and time—in very truth, "he broke through the barriers of the skies". He revealed to the wondering gaze of his contemporaries star upon star, system upon system, cluster upon cluster. Speaking of these revelations Horace Walpole said: "If there are twenty millions of worlds, why not as many and as many and as many more? Oh, one's imagination cracks!" His researches revealed the Earth in its true light—one revolving globule chained to a tiny star; a dust-grain in the infinite.
Every branch of observational astronomy bears to this day the impress of Herschel's powerful personality. Since his death, the science has greatly advanced; its horizons have widened, and innumerable new facts have been brought to light. Yet, even to-day, we cannot but agree with the verdict of a prominent American astronomer[1] that Herschel "was so far in advance of his age that we are just now beginning to appreciate his genius," and we may safely say that in the annals of astronomical science the name of William Herschel, pioneer of modern astronomy, will shine with increasing lustre as the years roll on. To him, indeed, we may apply, with peculiar fitness, the beautiful words of Longfellow:—
Were a star quenched on high,
For ages would its light,
Still travelling downwards from the sky,
Shine on our mortal sight.
So when a great man dies;
For years beyond our ken
The light he leaves behind him lies
Upon the paths of men.