waddling through the darkness with Varys at his side. He
Still another contemporary of D'Alembert and Delambre, and somewhat older than either of them, was Leonard Euler (1707-1783), of Basel, whose fame as a philosopher equals that of either of the great Frenchmen. He is of particular interest here in his capacity of astronomer, but astronomy was only one of the many fields of science in which he shone. Surely something out of the ordinary was to be expected of the man who could "repeat the AEneid of Virgil from the beginning to the end without hesitation, and indicate the first and last line of every page of the edition which he used." Something was expected, and he fulfilled these expectations.
In early life he devoted himself to the study of theology and the Oriental languages, at the request of his father, but his love of mathematics proved too strong, and, with his father's consent, he finally gave up his classical studies and turned to his favorite study, geometry. In 1727 he was invited by Catharine I. to reside in St. Petersburg, and on accepting this invitation he was made an associate of the Academy of Sciences. A little later he was made professor of physics, and in 1733 professor of mathematics. In 1735 he solved a problem in three days which some of the eminent mathematicians would not undertake under several months. In 1741 Frederick the Great invited him to Berlin, where he soon became a member of the Academy of Sciences and professor of mathematics; but in 1766 he returned to St. Petersburg. Towards the close of his life be became virtually blind, being obliged to dictate his thoughts, sometimes to persons entirely ignorant of the subject in hand. Nevertheless, his remarkable memory, still further heightened by his blindness, enabled him to carry out the elaborate computations frequently involved.
Euler's first memoir, transmitted to the Academy of Sciences of Paris in 1747, was on the planetary perturbations. This memoir carried off the prize that had been offered for the analytical theory of the motions of Jupiter and Saturn. Other memoirs followed, one in 1749 and another in 1750, with further expansions of the same subject. As some slight errors were found in these, such as a mistake in some of the formulae expressing the secular and periodic inequalities, the academy proposed the same subject for the prize of 1752. Euler again competed, and won this prize also. The contents of this memoir laid the foundation for the subsequent demonstration of the permanent stability of the planetary system by Laplace and Lagrange.
It was Euler also who demonstrated that within certain fixed limits the eccentricities and places of the aphelia of Saturn and Jupiter are subject to constant variation, and he calculated that after a lapse of about thirty thousand years the elements of the orbits of these two planets recover their original values.
THE PROGRESS OF MODERN ASTRONOMY
A NEW epoch in astronomy begins with the work of William Herschel, the Hanoverian, whom England made hers by adoption. He was a man with a positive genius for sidereal discovery. At first a mere amateur in astronomy, he snatched time from his duties as music-teacher to grind him a telescopic mirror, and began gazing at the stars. Not content with his first telescope, he made another and another, and he had such genius for the work that he soon possessed a better instrument than was ever made before. His patience in grinding the curved reflective surface was monumental. Sometimes for sixteen hours together he must walk steadily about the mirror, polishing it, without once removing his hands. Meantime his sister, always his chief lieutenant, cheered him with her presence, and from time to time put food into his mouth. The telescope completed, the astronomer turned night into day, and from sunset to sunrise, year in and year out, swept the heavens unceasingly, unless prevented by clouds or the brightness of the moon. His sister sat always at his side, recording his observations. They were in the open air, perched high at the mouth of the reflector, and sometimes it was so cold that the ink froze in the bottle in Caroline Herschel's hand; but the two enthusiasts hardly noticed a thing so common-place as terrestrial weather. They were living in distant worlds.
The results? What could they be? Such enthusiasm would move mountains. But, after all, the moving of mountains seems a liliputian task compared with what Herschel really did with those wonderful telescopes. He moved worlds, stars, a universe-- even, if you please, a galaxy of universes; at least he proved that they move, which seems scarcely less wonderful; and he expanded the cosmos, as man conceives it, to thousands of times the dimensions it had before. As a mere beginning, he doubled the diameter of the solar system by observing the great outlying planet which we now call Uranus, but which he christened Georgium Sidus, in honor of his sovereign, and which his French contemporaries, not relishing that name, preferred to call Herschel.
This discovery was but a trifle compared with what Herschel did later on, but it gave him world-wide reputation none the less. Comets and moons aside, this was the first addition to the solar system that had been made within historic times, and it created a veritable furor of popular interest and enthusiasm. Incidentally King George was flattered at having a world named after him, and he smiled on the astronomer, and came with his court to have a look at his namesake. The inspection was highly satisfactory; and presently the royal favor enabled the astronomer to escape the thraldom of teaching music and to devote his entire time to the more congenial task of star-gazing.
- gruffly, explaining that he had always been fond of the
- expanse of sandy plain. Evidently it was too dry for game,
- breast. The stretch of cliff that connects them appears
- about sixty yards from us, his boot, polished by the dry
- the steps again, finding himself now nearly up to his armpits
- that Good, mindful of his marvellous shot at the giraffe,
- pointed to Umbopa. I looked at Umbopa as he said it, and
- At one place we came to a ravine three hundred feet broad
- end of the apartment. A steady stream of dirty water was
- with a snap. It was a most fortunate move, for next second
- The solitary bull stood fifty yards or so to this side
- The two Winchester repeating rifles (for Umbopa and Ventv?gel),
- and phlox that drew him to the perfumed air of the garden,
- were standing together, and I could see, from their unquiet
- saw the hands of some of the men steal down to their sides,
- feet deep, and in a third it tunnelled through the base
- the light upon them. They led upward. He mounted cautiously,
- tusks. I whispered to the others that I would take the
- a woman’s breasts, and at times the mists and shadows
- here they were cold, straight into the mouth of the cave.
- skin, how he had passed the night. He seemed perfectly
- him struggling with that stubbly beard. It seemed so very
- into the unknown; and there doubtless he will still sit,
- dragged ourselves. As luck would have it, here we found
- without actually submerging his head, and to regain the
- Two curious things struck us as we gazed. First, that the
- halt about two o’clock in the morning, we trudged on
- she came up, beautiful and serene as ever, and, with one
- our tents. They were very civil, and offered us a house;
- take much further interest in the green growth, for one
- The others saw also, and the sight proved too much for
- a new difficulty arose, we had no fuel, and therefore could
- Korak fast was becoming but a memory. That he was dead
- to his face. The Zulu laughed a quiet little laugh which
- dragged ourselves. As luck would have it, here we found
- mountains where all things perish. But what do your lies
- lamp was incapable of penetrating the fog. He groped with
- the soft air murmured through the leaves of the silver
- of old da Silvestra’s map, he will see that the desert
- business travelling along down hill on that magnificent
- composed. When we reached Lemuy we had much difficulty
- him as fast as our wearied limbs would carry us, hoping
- feather, it is the seed of the grass, blown hither and
- in the sand, his eye-glass still fixed firmly in his eye,
- might have noticed the reduced numbers of his following.
- eight miles away. At the distance it looked like an ant-hill,
- each article neatly, placed it out of the dew under a corner
- did not shoot at them, as we had plenty of meat. They trotted
- He ducked rapidly, almost touching the muddy water with
- Thought that Ventv?gel would have died during the night.