"It may deserve the honorable society's thoughts, how so great a quantity of vapor should be raised to the top of the atmosphere, and there collected, so as upon its ascension or otherwise illumination, to give a light to a circle of above one hundred miles diameter, not much inferior to the light of the moon; so as one might see to take a pin from the ground in the otherwise dark night. 'Tis hard to conceive what sort of exhalations should rise from the earth, either by the action of the sun or subterranean heat, so as to surmount the extreme cold and rareness of the air in those upper regions: but the fact is indisputable, and therefore requires a solution."
From this much of the paper it appears that there was a general belief that this burning mass was heated vapor thrown off from the earth in some mysterious manner, yet this is unsatisfactory to Halley, for after citing various other meteors that have appeared within his knowledge, he goes on to say:
"What sort of substance it must be, that could be so impelled and ignited at the same time; there being no Vulcano or other Spiraculum of subterraneous fire in the northeast parts of the world, that we ever yet heard of, from whence it might be projected.
"I have much considered this appearance, and think it one of the hardest things to account for that I have yet met with in the phenomena of meteors, and I am induced to think that it must be some collection of matter formed in the aether, as it were, by some fortuitous concourse of atoms, and that the earth met with it as it passed along in its orb, then but newly formed, and before it had conceived any great impetus of descent towards the sun. For the direction of it was exactly opposite to that of the earth, which made an angle with the meridian at that time of sixty-seven gr., that is, its course was from west southwest to east northeast, wherefore the meteor seemed to move the contrary way. And besides falling into the power of the earth's gravity, and losing its motion from the opposition of the medium, it seems that it descended towards the earth, and was extinguished in the Tyrrhene Sea, to the west southwest of Leghorn. The great blow being heard upon its first immersion into the water, and the rattling like the driving of a cart over stones being what succeeded upon its quenching; something like this is always heard upon quenching a very hot iron in water. These facts being past dispute, I would be glad to have the opinion of the learned thereon, and what objection can be reasonably made against the above hypothesis, which I humbly submit to their censure."
These few paragraphs, coming as they do from a leading eighteenth-century astronomer, convey more clearly than any comment the actual state of the meteorological learning at that time. That this ball of fire, rushing "at a greater velocity than the swiftest cannon-ball," was simply a mass of heated rock passing through our atmosphere, did not occur to him, or at least was not credited. Nor is this surprising when we reflect that at that time universal gravitation had been but recently discovered; heat had not as yet been recognized as simply a form of motion; and thunder and lightning were unexplained mysteries, not to be explained for another three-quarters of a century. In the chapter on meteorology we shall see how the solution of this mystery that puzzled Halley and his associates all their lives was finally attained.
BRADLEY AND THE ABERRATION OF LIGHT
Halley was succeeded as astronomer royal by a man whose useful additions to the science were not to be recognized or appreciated fully until brought to light by the Prussian astronomer Bessel early in the nineteenth century. This was Dr. James Bradley, an ecclesiastic, who ranks as one of the most eminent astronomers of the eighteenth century. His most remarkable discovery was the explanation of a peculiar motion of the pole-star, first observed, but not explained, by Picard a century before. For many years a satisfactory explanation was sought unsuccessfully by Bradley and his fellow-astronomers, but at last he was able to demonstrate that the stary Draconis, on which he was making his observations, described, or appeared to describe, a small ellipse. If this observation was correct, it afforded a means of computing the aberration of any star at all times. The explanation of the physical cause of this aberration, as Bradley thought, and afterwards demonstrated, was the result of the combination of the motion of light with the annual motion of the earth. Bradley first formulated this theory in 1728, but it was not until 1748--twenty years of continuous struggle and observation by him--that he was prepared to communicate the results of his efforts to the Royal Society. This remarkable paper is thought by the Frenchman, Delambre, to entitle its author to a place in science beside such astronomers as Hipparcbus and Kepler.
Bradley's studies led him to discover also the libratory motion of the earth's axis. "As this appearance of g Draconis. indicated a diminution of the inclination of the earth's axis to the plane of the ecliptic," he says; "and as several astronomers have supposed THAT inclination to diminish regularly; if this phenomenon depended upon such a cause, and amounted to 18" in nine years, the obliquity of the ecliptic would, at that rate, alter a whole minute in thirty years; which is much faster than any observations, before made, would allow. I had reason, therefore, to think that some part of this motion at the least, if not the whole, was owing to the moon's action upon the equatorial parts of the earth; which, I conceived, might cause a libratory motion of the earth's axis. But as I was unable to judge, from only nine years observations, whether the axis would entirely recover the same position that it had in the year 1727, I found it necessary to continue my observations through a whole period of the moon's nodes; at the end of which I had the satisfaction to see, that the stars, returned into the same position again; as if there had been no alteration at all in the inclination of the earth's axis; which fully convinced me that I had guessed rightly as to the cause of the phenomena. This circumstance proves likewise, that if there be a gradual diminution of the obliquity of the ecliptic, it does not arise only from an alteration in the position of the earth's axis, but rather from some change in the plane of the ecliptic itself; because the stars, at the end of the period of the moon's nodes, appeared in the same places, with respect to the equator, as they ought to have done, if the earth's axis had retained the same inclination to an invariable plane."
- the catacombs. Max glanced at the white face of Helen Cumberly,
- New Mexico. His granddaughter, Mrs. Lucy Keys, of Woods,
- An aged Indian, who had spent many years in a white settlement,
- Expedition in 1805, of whom thirty-four were men, and one
- of an ancient tertiary epoch) of which these islands are
- He then took the likeness of General Washington from his
- Seattle, Red Jacket, Cornstalk, Tomo-Chi-Chi and Pokagon.
- and scooped himself a kind of rifle-pit. Then, with a pile
- in which they are here mentioned, expressing their respective
- from the venison and intimated by signs that he was hungry
- Shabbona, the White Man's Friend, the Pottawatomie chief,
- effect. At last he hit upon an expedient, which none save
- very slowly northward along the trail that connects with
- trackless plains, better equipped for the adventure. And
- Chief Leatherlips of the Wyandots, who was executed by
- that the people were shamefully deficient in enterprise
- to tell him that she loved him. A dozen times she thought
- then coolly swung himself to the ledge which commanded
- it, in a vain endeavor to find the solution to what was
- are weeping over them; wives are lamenting as they bend
- to have a good idea of time, was employed to strike the
- The Indians observed the pictures which Mr. Holmes threw
- running conversation, and when he poured the last dipper
- President he appointed him Commissioner of Indian Affairs,
- and the land was wooded down to the water’s edge. In
- And will gunpowder grow like corn? exclaimed half a dozen
- Isaac?' and he answered: 'It is the custom for the man
- nor notched trees to guide her, it is not surprising that
- he often spent much time with the white foreman of the
- The price was quoted and was followed by another query
- and the Mohawk was determined to have the life of an enemy
- about 'squaw men' asked if the white women who marry Indian
- fowls, sheep, goats, pigs, horses, and cattle; the order
- the instruction of any who might come to him to be taught.
- to be erected a statue of this noble red woman. Those who
- credit of, and he wished to put some mark upon his work
- Max crossed the threshold hard upon her heels. Three descending
- since then it has been the custom to allow condemned Indians
- much apparent relish, and lay down again and was soon sleeping
- away, upon a kind of shelf, in a small cave, where nothing
- that belief he had made no effort to find her after his
- Swelling himself up to the highest tension, he strode up
- tribe meaning woman, but it has since come to be used commonly
- him and take him to camp alive, so that all the other Indians
- of three-halfpence, two fowls, one of which, the Indian
- on the road; and I can only account for the occurrence
- genius, and determined to invent a system of writing his
- John Jaybird, known among both whites and Indians as the
- the great caravan routes entering the Sahara from the south.
- He refused to acquire the English language, and never dressed