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to describe the laws of the actions of the spirit or agent by which this attraction is performed.
And for the same reason he is silent about the cause of gravity, there occurring no experiments or phenomena by which he might prove what was the cause of it. And this he has abundantly declared in his Principles, near the beginning, in these words, “ I do not enquire into the physical causes and seats of forces."
And a little after, “ I indifferently and promiscuously use for each other the words attraction, impulse, or any kind of propension towards the centre, by considering these forces not physically but mathematically. Whence I would caution the reader not to think, that by these words I define the species or manner of the action, or the physical cause or reason; or that I truly and physically ascribe forces to centres, which are only mathematical points, if I should happen to say, that either the centres attract, or that there are central forces." And at the end of his Optics, “ Here I do not enquire by what efficient cause these qualities, viz. gravity, the magnetic and electrical forces, are produced. What I call attraction may possibly be produced by impulse, or in some other manner unknown to us.
By attraction, I would here be understood to mean only in general, a certain kind of force, whereby bodies mutually tend towards each other, whatever cause that quality may be ascribed to. For we must first necessarily know by phenomena of nature what bodies mutually attract each other, and what are the laws and properties of that attraction, before we can properly enquire by what efficient cause that attraction is produced.” And a little after he mentions the same attractions as forces which by phenomena appear to have a being in nature, though their causes be not yet known; and distinguishes them from occult qualities, which are supposed to flow from the specific forms of things. And in the scholium at the end of his Principles, after he had mentioned the properties of gravity, he added, " But the reason of these properties of gravity I could not deduce from phenomena, and I do not devise hypotheses. For whatever is not deduced from phenomena is to be called an hypothesis ; and hypotheses, whether metaphysical or physical, or of occult or mechanical qualities, have no place in experimental philosophy. It is sufficient that gravity really exists, and acts according to the laws I have explained, and that it solves all the motions of the celestial bodies and of our sea. And after all this, one would wonder that Mr. Newton should be reflected on, for not explaining the causes of gravity, and other attractions by hypotheses; as if were a crime to content himself with certainties, and let uncertainties alone.
An Account of a Journey from the Port of Oratava, in the
Island of Teneriffe, to the Top of the Peak in that Island, in
BETWEEN La Stancha and the top of the Peak there are two very high mountains besides the Sugar-loaf, each of which mountains is almost half a mile's walking: on the first of them the rubbish is small, and we were apt to slip back as we stepped upwards. But the uppermost is all composed of hard loose rocky great stones, cast together in a very confused order. After resting several times, we came to the top of the first mountain, where we drank every one a little wine, and ate a bit of gingerbread. Then, being pretty well refreshed, we set forwards again to ascend the second mountain, which is higher than the first, but is better to walk on, because of the firmness of the rocks. After we had tra. velled for about half an hour up the second mountain, we came within sight of the Sugar-loaf, which before we could not see by reason of the interposition of these great hills. After we were arrived to the top of this second mountain, we came to a way that was almost level, but rather ascending ; and about a furlong farther is the foot of the Sugar-loaf, which we soon reached. Then looking upon our watches, we found it to be just three o'clock. The night was clear where we were and the moon shone very bright; but below, over the sea, we could see the clouds, which looked like a valley at a prodigious depth below us. We had a brisk air, the wind being S. E. by S., as it was for the most part while we were on our journey.
While we sat at the foot of the Sugar-loaf, resting and refreshing ourselves, as before in other places, we smoke break out in several places, which at first looked like little clouds, but they soon vanished; others not long after succeeding them, from the same or other places. We set forwards to ascend the last and steepest part of our journey, viz. the Sugar-loaf, exactly at half past three, and after we had rested twice or thrice, we all arı ed there by four.
The shape of the top of the Peak is partly oval, the longest diameter lying N.N.W. and S. S. E., and is, as near as I could guess, about 140 yards long; the breadth the other way being about 110. Within the top of the Peak is a very deep hole, called the Caldera, or Kettle, the deepest part of which
lies at the south end: it is, I believe, 40 yards deep, reckoning from the highest side of the Peak; but it is much shallower reckoning from the side opposite to Garachica. The sides of this kettle are very steep, in some places as steep as the descent on the outside of the Sugar-loaf. We all went to the bottom of this kettle, where a great many very large stones lie, some of them above six feet in height. The earth that is within-side the kettle being rolled up long and put to a candle, will burn like brimstone. Several places within-side the top of the Peak are burning, as on the outside ; and in some places, on turning up the stones, is found very finë brimstone or sulphur sticking to them. At the holes where the smoke comes out, there also comes forth a great heat, so hot that one cannot endure one's hand there long. At the N. by E. side, within the top, is a cave, where we found a dead goat; in which cave sometimes the true spirit of sulphur distils, as they say, but it did not drop while I was there.
The report is false about the difficulty of breathing upon the top of this place; for we breathed as well as if we had been below : we ate our breakfast there, and I was there in all for about two hours and a quarter. Before the sun rose I think the air was as cold as I have known it in England, in the sharpest frost I was ever in: I could scarcely endure my gloves off. There was a great dew all the while we were there till sun-rising, which we could find by the wetness of our clothes; but the sky looked there as clear as possible. A little after sun-rising we saw the shadow of the Peak on the sea, reaching over the island of Gomera; and the shadow of the upper part, viz. of the Sugar-loaf, we saw imprinted like another peak in the sky itself, which looked very surprising: but the air being cloudy below us, we saw none of the other islands, except Grand Canaria and Gomera.
A short History of the several New Stars' that have appeared
within these 150 Years. By Dr. HALLEY. - [1715.] Whether it be owing to the greater diligence of the moderns, or that in reality no such thing has happened for many agés past, I will not undertake to determine ; but this is certain, that within the space of the last 150 years more discoveries have been made of changes among the fixed stars than in all antiquity before.
Ist. That in the chair of Cassiopeia was not seen by Cornelius Gemma on the 8th of November, 1572, who says, he that night considered that part of heaven in a very serene
sky, and saw it not: but that the next night, November 9., it appeared with a splendour surpassing all the fixed stars, and scarcely less bright than Venus. This was not seen by Tycho Brahe before the 11th of the same month, but from thence he assures us that it gradually decreased and died away, so as in March, 1574, after 16 months, to be no longer visible; and at this day no signs of it remain.
Such nother star was seen and observed by the scholars of Kepler, to begin to appear on Sept. 30., O. S. 1604, which was not to be seen the day before : but it broke out at once with a lustre surpassing that of Jupiter ; and like the former it died away gradually, and in much about the same time disappeared totally, there remaining no traces of it in Jan. 1605-6.
But between them, viz. in the year 1596, we have the first account of the wonderful star in collo ceti, seen by David Fabricius on the third of August, O.S., as bright as a star of the third magnitude, which has been since found to appear and disappear periodically; its period being nearly seven revolutions in six years, though it returns not always with the same lustre. Nor is it ever totally extinguished, but may at all times be seen with a six-foot tube.
Another new star was first observed by Will. Jansonius, in the year 1600, in pectore, or rather in eductione colli cygni, which exceeded not the third magnitude. This having continued some years, became at length so small, as to be thought by some to disappear entirely : but in the years 1657, 1658, and 1659, it again rose to the third magnitude, though soon after it decayed by degrees to the fifth or sixth magnitude, and at this day is to be seen as such.
A fifth new star was first seen and observed by Hevelius, in the
year 1670, on July 15. O.S., as a star of the third magnitude; but by the beginning of October it was hardly to be perceived by the naked eye. In April following it was again as bright as before, or rather greater than of the third magnitude, yet wholly disappeared about the middle of August. The next year, in March, 1672, it was seen again, but not exceeding the sixth magnitude : since then, it has been no further visible.
The sixth and last, is that discovered by Mr. G. Kirch, in the year 1686, and its period determined to be of 4044 days; and though it rarely exceeds the fifth magnitude, yet is it very regular in its returns, as we found in the year 1714. Since then, we have watched, as the absence of the moon and the clearness of weather would permit, to observe the
first beginning of its appearance in a six-foot tube, which bearing a very great aperture discovers most minute stars. And on June 15. last, it was first perceived like one of the very least telescopical stars : but in the rest of that month and July it gradually increased, so as to become in August visible to the naked eye; and so it continued all the month of September. After that it again died away by degrees, and on the eighth of December at night it was scarcely discernible by the tube, and as near as could be guessed, equal to what it was at its first appearance on June 15th : so that this year it has been seen in all near six months, which is but little less than half its period : and the middle, and, consequently, the greatest brightness, falls about the 10th of September.
An Account of some large Teeth lately dug up in the North of
Ireland. By Mr. Francis NEFILE. — [1715.] SEVERAL large teeth were lately found within eight miles of Bulturbet, at a place called Maghery, in part of the Bishop of Killmore's lands, on digging the foundation for a mill near the side of a small brook, that parts the counties of Cavan and Monoghan.
There are in all four teeth, two of a larger and two of a smaller sort; the larger one is the farthest tooth in the under jaw; the other is like it, and belongs to the opposite side ; the lesser tooth I take to be the third or fourth tooth from it, and has its fellow : these are all that were found, and one of them in a piece of the jaw-bone, which mouldered away as soon as taken out of the earth; there was part of the skull found also of a very large size and thickness, but as soon as exposed to the air, it mouldered away as the jaw had done.
Some few pieces of other bones were found, but none entire ; yet by those bits that were found, one might guess that they were parts of those that were of a larger size.
The place where this monster lay was about four feet under ground, with a little rising above the superficies of the earth, which was a plain under the foot of a hill, and about 30 yards from the brook. The bed on which it lay had been laid with fern, with that sort of rushes here called sprits, and with bushes intermixed, and nut-shells. The branches of the fern, in every lay as we opened them, were very distinguishable, as were the seeds of the rushes and the tops of boughs.
The two large teeth are of equal weight, 2 lb. each ; the