HERSCHEL AND THE STORY OF THE STARS, 1738–1822.

[114] The early state of society is sometimes called the childhood of the race, when none of the questions which vex the human mind had yet been asked and mankind accepted all things as a child does, without doubt or comment.

And as the child looks without wonder on all the marvels of creation, and fears nothing, knowing that the day-world, with all its beauty, will only fade away to be supplanted by the night-world, with its charm of star and moon and dream, so did the early races look with the same unquestioning eyes upon the succession of day and night, and starlight and sunlight were to them but two separate kingdoms, over which they had equal dominion but of whose resources they had no knowledge.

[115] The Chaldeans and Egyptians were the first nations who have left us records of their studies of the world of nature, and it is to them that we owe the faint beginnings of scientific thought. Believers in a fate or destiny which ruled all the affairs of men from the greatest to the smallest, they sought, in every manifestation of nature, a sign, or lesson, and their faith in the influence of the stars upon the lives of men gave to the study of the heavens a special value.

This superstition passed, with the progress of knowledge, into the minds of other nations, and among the Greeks there early arose a separate class of students called astronomers, from the word aster, a start, which had for its object the study of the stars, and it was from this desire to connect all the working of nature with the affairs of daily life that the science of astronomy was born.

For ages the stars and planets, "the lamps of heaven," were regarded with a superstitious awe, and the old faith of the Chaldean priests could be found living in the breasts of the mystics of the Middle Ages, long after the race [116] had outgrown its childhood, and astrology, the science which professed to foretell the fate of man from the constellation which ruled at his birth, still flourished when the advancements of thought had brought about a state of society in which science and the arts played an important part.

But modern thought finally freed itself from this intellectual bondage, and set about the study of the stars in the same practical manner that a seaman would undertake a voyage of discovery, and from that time astronomical knowledge made rapid progress.

Among the greatest of modern astronomers was William Herschel, who was born in the city of Hanover in 1738. His father was an oboeist in the Hanoverian Guards, and the child's first impressions were connected with the little musicales that were held every evening in the unpretentious family sitting-room. Money was scarce in this obscure little household, the father's salary hardly sufficing to bring needed comforts to the children, but there was not a happier family in the city, for all that. The [117] father had all a musician's love for his art, and wanted nothing more, when his hours of duty and teaching were over, than to gather his children around him and improvise a family concert, training the little performers with earnest care, noticing their improvement with fatherly pride, and refreshing himself with the thought that he was supplying them with a resource that, no matter how hard their lot might be, would always be a comfort and help to them in the future.

William was the second son, and very early was considered an important personage in the family group, showing an extraordinary taste for music, and developing a great talent for discussion; for, besides their musical bent, the family were given to grave talks about everything that attracted their attention. As the children grew older the father adapted these conversations to subjects best suited to develop their minds, and art and philosophy were as eagerly discussed as music. Sometimes, before the evening was over, they would all go out of doors, and spend an hour in studying [118] the constellations and listening to their father's remarks on astronomy, which seemed just as interesting to them as their lessons in music, although it was quite understood that all the sons were to be musicians, a calling that seemed the most honorable and enviable of any to the entire family.

With the idea of initiating them as early as possible into the mysteries of their chosen professions, the father allowed them from time to time to take part in public concerts, their talent being so unusual that even as children they were given solo parts to play, and thus, while yet a little boy, the future astronomer was made to assume certain responsibilities, and to look upon life seriously.

The Herschel boys attended the garrison school in Hanover, where they learned the ordinary branches, their father taking care that any deficiency in the course should be supplied at home, and letting them feel that in all their pursuits and enjoyments he wished to be their companion and friend. It was necessary, however, for the children to aid in the support of [119] the family as soon as possible, and therefore the two oldest sons were yet lads when they entered the guards, William accepting the position of oboe-player. The family concerts, however, still continued, only interrupted by the making of musical instruments and all sorts of mechanical toys, for which the father and sons had a fancy, and the family discussions still formed an interesting part of their life, more than half the night often being passed in animated talk as to the merits of the different artists, philosophers, and naturalists who were then famous.

William remained in the army for four years, one year of which was spent in England, and at the age of nineteen left the guards on account of delicate health, and returned to England, with the hope of being able to earn his living there.

A less enterprising youth might have been dismayed at the prospect of being homeless and friendless in a foreign land, but Herschel did not consider his lot by any means hopeless. He could speak English well enough to make [120] himself understood, could play on the oboe, violin, and organ with sufficient skill to assure him some kind of a living, and, above all, his wants were few and modest; and so his new life in England did not frighten him, and he began it with a brave heart.

Some years were spent by the young musician in wandering from one town to another, without having any permanent employment, but finally he came under the notice of Dr. Miller, a well-known organist of Durham, who was so delighted with Herschel's rendition of the works of his favorite composers that he invited him to come and live with him, promising to do all that he could to advance him in his profession. Herschel accepted this generous offer in the same good faith in which it was made, and from this time his success was assured.

Miller's influence procured him the place of first violin in the popular concerts at Durham, where he speedily became a favorite, and was soon offered as may pupils as he could take; and as his popularity spread he was offered one advantageous position after another, until he [121] was finally appointed organist of the principal church in Bath, where the gay society and intelligent companionship of his new friends, together with increased means at his disposal and larger facilities for study, made up a life as pleasant as could be desired.

Herschel was at this time about twenty-eight years old, and had made such progress in music that he soon began to publish his compositions, and to have the satisfaction of seeing them favorably received by the public. At this time, although an earnest student and devoting every spare moment to study, he seems to have had no other ambition than to become a good musician; and in order to accomplish this, he began a careful study of harmony, using for his instruction a work on harmonics which then enjoyed considerable fame. The study of harmony is dependent upon a knowledge of mathematics, and this led to kindred subjects. The author of the "Harmonics" had also written a work on optics, which fascinated Herschel to such a degree that he pored over it every leisure moment of the day, and spent [122] long hours of the night in studying it. His interest was turned in this way to astronomy, and so absorbed did he become in this subject that he had no rest until he had procured a telescope and looked out all the objects in the heavens which were described in the books. And when this point was reached, his true work in life first began. From the time that he first saw the magnificent spectacle of the heavens revealed to him in its hitherto unknown splendor, he devoted himself to its study with an ardor that made all his previous interests seem insignificant.

Pupils were dismissed in order to gain more time for study and observation, although he could not well spare the money, and his brother and sister, who now lived with him, were drawn off from their musical studies and pressed into the service of making telescopes and other instruments necessary for surveying the heavens.

The brother and sister gave themselves to the new work with the energy that characterized the family; and soon the house was turned into [123] a huge workshop, and stands, tubes, and mirrors were turned out as fast as possible.

Herschel became so engrossed that he would not leave the workshop even for his meals, and his sister could only induce him to eat by standing by his side and putting the food into his mouth, while at the concerts and theatres where he led large orchestras, it was no uncommon thing for him to rush out between the acts and spend the time in snatching brief glimpses of the heavens. This industry was well rewarded, for Herschel was so successful in his experiments that he was able to produce telescopes far superior to any that had yet been made, and received quite an addition to his income by the sale therefrom; and the careful study of the heavens which he then began proved of infinite service to him later on.

Herschel's great object was to make a more thorough survey of the stars than had yet been attempted, and, in order to do this, he mapped out the heavens in sections, determining to study each part with the greatest care; and so earnestly did he carry out this plan that for years [124] he never went to bed of a clear night while a star was visible, remaining winter and summer in the open air until the day dawned. While thus engaged Herschel noticed one night a star of different appearance and much larger than the small stars near it, and a careful observation for two or three nights showed him that the body did not remain stationary, and scintillate as the stars, but that it shone with a steady light and appeared to change its place. Herschel thereupon decided that he had found a new comet, and at once announced the discovery to the world. All the astronomers of Europe immediately turned their attention to this interesting object, and mathematicians at once began to observe its motions and calculate from them the size and shape of its orbit. All the comets that were known had been found to have orbits very elliptical in form, but, after many months of calculation, astronomers were forced to admit that the new comet could not move in an orbit similar to those of other comets, but that, on the contrary, it was travelling in a path only slightly elliptical, like that of the earth and other planets.

[125] This conclusion at once led to the suggestion that perhaps the new object was not a comet, after all, but a planet, and, startling as this idea seemed, it was finally demonstrated by the French astronomer Laplace, that Herschel had really discovered a new planet.

The world of science was electrified by this discovery, which was not only the greatest that had been made by the telescope since the splendid revelations of Galileo, but the greatest that had ever been made. The other planets had been known as far back as the memory of man extended, and the finding of new stars, or of the satellites of the planets, seemed of much less importance than the discovery that there was still another member of the system of planets, like them bound by the mysterious influences that held them together, and performing its regular revolution around the sun, although its presence had been unknown and unsuspected through all the countless ages of the world.

Astronomy was invested with a new interest, and all eyes were turned with eager gaze to the starry fields of heaven, for who could tell [126] what new wonder might not be found, far away in the dim recesses of space?

And in the meantime honors were showered upon the one who had read this new secret, and who had hitherto only been known to the world as a clever amateur astronomer who had spent the intervals between his musical studies in writing a theory on the height of the mountains of the moon, or in manufacturing telescopes.

Herschel wished to name the new planet after George III., King of England, but this was objected to by other astronomers, some of whom proposed to call it after its discoverer and others thinking it would be more in harmony with the traditions of science to give it the name of one of the old Greek deities. These last carried the day, and the planet was finally named Uranus, after the oldest of the gods.

Uranus was discovered on the 13th of March, 1781. It had been before this mapped as a star, and, in order to connect the discovery of its planetary character with the name of Herschel, its sign in astronomical records is the letter H with a suspended orb.

[127] It was now generally acknowledged that the labors of such a genius as Herschel should be devoted to science alone, and accordingly the king granted him a pension which enabled him to give up teaching. Some time after this the family moved to Slough, where there were better opportunities offered for study, and Herschel at once began the construction of an immense telescope which, when finished, greatly aided him in his survey of the heavens.

A new satellite of Saturn was discovered the day after the completion of the great telescope, and in 1787 it was found that Uranus was furnished with two moons. This discovery filled Herschel with delight, being added proof of the harmony that extended throughout the universe. Before making it known, and in order to be absolutely sure that he had not been mistaken, Herschel prepared a sketch of Uranus and his revolving satellites as they would appear on a certain night, and great was his joy, when the moment came, to find that the position and appearance of the group exactly corresponded to his drawing.

[128] This experiment seemed to give him a greater hold than ever upon the secret of the heavens, which he spoke of as a luxuriant garden filled with choice flowers, whose life might be watched from the bursting of the seed through all the successive stages of foliage, bloom, maturity, and decay, just as plants are studied from the time of the sowing of the seed to the fall of the last leaf in autumn.

Two thousand years before the time of Herschel a catalogue of the stars had been executed by Hipparchus, the Greek astronomer, who was led to the work by the appearance of a new star of unusual brilliancy which disappeared after a while from the heavens. And although from time to time after this, star-catalogues were prepared, it was reserved for Herschel to make the first thorough and systematic attempt to construct a catalogue in which the stars were classified according to their relative brightness. In preparation of this catalogue the conclusion was reached by Herschel that there are certain stars which appear and disappear, and others, whose light increases and diminishes for no [129] known reason. Such stars are called variable stars, and it is of the utmost consequence in preparing a catalogue to take these into account. In catalogues, the stars are classed as of the first magnitude, second magnitude, and so on, according to their brightness. Stars of the sixth magnitude are visible to the naked eye, while the telescope even reveals those of the seventeenth magnitude; but these numbers do not signify the actual degrees of brightness, as a star of the first magnitude shines with one hundred times the brilliance of one of the sixth.

When viewed through a telescope, certain stars which appear only as brilliant points to the naked eye can be separated into one or more stars, and a careful study of these interesting bodies led Herschel to one of his grandest discoveries.

He observed these stars through several years, and at last came to the conclusion that in all cases of double stars one revolved around the other, just as the moon revolves around the earth.

Newton's system of gravitation bound the [130] earth and planets to the sun, and made of the solar system a harmonious whole, but Herschel's discovery of the revolution of one star around another went even further than this, and extended the harmony to the farthest regions of space, and the grandeur of this discovery was alone sufficient to make the name of Herschel famous in the history of science.

In connection with his study of the stars, Herschel undertook to measure their distances from the earth, and to find out if their brightness depended upon their nearness to or remoteness from us. And after a long series of careful experiments, he determined that if stars of the first magnitude, like Sirius and Arcturus, were removed twelve times their actual distance, they would be just visible to the naked eye, while if stars which are only now to be seen through a telescope were to be brought nearer to the earth so as to be only one-tenth as far away as they now are, they would shine with the brightness of the largest and most brilliant stars. He concluded, therefore, that the brightness of the stars depended on their distance, and that the fainter stars were the more distant [131] ones, and even devised a method based on this idea by which their relative distances would be ascertained.

It is now known that he was wrong in this view, for some of the faintest stars have been found to be among those nearest the earth; but the difficulties met in determining star-distances are so great that it was not till sixteen years after the death of Herschel, and when the instruments for making observations had been greatly improved, that the distance of a fixed star was actually measured. Herschel's investigations and experiments on the light of the stars and their distance led the way to some of the most valuable and wonderful results of modern astronomical research and have given him the position of a pioneer in the science.

In connection with these studies, Herschel also took up the subject of the nature of the sun and its place in the universe. The accepted theory of the sun's nature was that it was a solid, surrounded by a luminous atmosphere which gave it its brightness, and this theory, with some changes, was also held by Herschel. But his deductions in regard to the sun's place [132] in the universe were of more importance. His discovery of the revolution of double stars could only lead to speculation with regard to all the objects of creation, and it was but natural to conclude that motion, which was a property of so many, should belong to all.

Observations extended from the time of the ancients had led to the conclusion that some of the largest stars of the first magnitude had changed their places within the historic period, and they were therefore supposed to have an individual motion, and from this fact Herschel argued a corresponding motion for the sun, which he decided was itself a small star. He therefore began a series of experiments, and finally came to the conclusion that the sun, with all his attendant company of planets and comets, was in reality moving through space at a marvellous rate of progress, and that, in accordance with the law of gravitation, he was passing through an orbit of inconceivable magnitude having for its centre one of the remote stars.

It has been thought that this great central fire whose mighty forces thus govern the mech- [133] anism of the solar system is the star Alcyone, in the Pleiades, but of this we cannot be sure. We only know that the sun, with his great retinue of revolving worlds, is moving toward some unknown point in the heavens, and that the stars, which were once thought to be brilliant globes firmly fixed in crystal spheres, are in reality probably the centres of attendant planets which they carry with them in their majestic progress through the boundless regions of space; and that, if it were possible to view the heavens as they really are, we should see an infinite number of such systems, with orbitals crossing and recrossing, in the most intricate manner, but in place of the apparent confusion and entanglement there exist the most exquisite order and symmetry.

Herschel's study of the heavens also included observations on those cloud-like appearances called nebulæ which are seen in various constellations, and of which the Milky Way is the greatest example.

From the earliest times this broad band of light had attracted the attention of mankind, [134] and many quaint legends were connected with it. The Romans called it the Highway of the Gods, and in later times it was sometimes spoken of as Jacob's Ladder;  but even among the ancients some true idea of its character existed, for Pythagoras declared that the Milky Way was only a great assemblage of stars, and Galileo's telescope had proved that in the main the theory of the old Greek was correct. At first Herschel was led to believe that all nebulæ could be seen to be made up of stars, if viewed through a sufficiently powerful telescope. But later he changed his opinion, and came to the conclusion that there were two kinds of nebulæ—the resolvable, which are made up of great star-clusters which have a cloudy appearance from their immense numbers and great distance, and the irresolvable, which are immense masses of self-luminous matter which gradually is condensing into solids like the sun and stars. This last idea was not new to Herschel, for Tycho Brahé and Kepler had both suggested that the "new stars" which appeared from time to time might be caused by [135] the condensation of the ether which filled all space. And although all "new stars" are really believed now to belong to the temporary stars which appear and disappear with regularity, yet the thought that the universe had been evolved out of such matter shows in a marked degree the originality and boldness of Kepler's genius.

The French astronomer Laplace, a contemporary of Herschel, also held this theory of the nebulæ, which he published in a work called the "Nebular Hypothesis."

Laplace conceived that the solar system consisted originally of matter in the form of gas or vapor of an enormously high temperature; that as it cooled unequal currents were formed, which gradually caused it to rotate; that its rate of motion increased until the outside, which was of a lower temperature than the centre, would become detached and break up into smaller parts; that these parts came together finally and formed spheroidal masses which revolved around the centre; that the sun was what was left of the original matter, and the planets and asteroids were the parts that had been thrown [136] off. This theory, which had its foundation in the action of the law of gravitation, may apply not only to the solar system but to the entire universe, and Herschel's idea of the irresolvable nebulæ, consisting of a shining fluid which was solidifying into stars, has been supported by later astronomers, for when the light from these nebulæ has been analyzed it has given out the colors of matter in a state of gas, while an analysis of the light of the stars gives a very different result.

And thus Herschel's comparison of the heavens to a flower-garden may be seen to have a deeper significance than would at first appear; and if we consider the claims of the nebular hypothesis, we might say that the nebulæ are the great seed-repositories of nature, from which are evolved all the stars and planets which, passing through the time of bloom and maturity, come at last to a state resembling that of the dead moons—the withered flowers of these celestial gardens—from which all life has passed away.

Herschel made many observations on light [137] and heat in connection with his other studies, but he is chiefly remarkable for his exhaustive survey of the stars.

He died in 1822, at the age of eighty-four, preserving his great mental powers till the last, and claiming, with truth, that he had looked farther into space than any other eye had yet penetrated.

The nebular hypothesis which his researches helped to formulate is as yet but an unproved theory, and whether it embodies the true secret of creation or not we cannot tell.