Imágenes de páginas
PDF
EPUB

referred to the Bafha of Caigotswho is fure to divide the in1 heritance among all the brothers. This sentence not being agreeable to them, they fight it out, and he that conquers, mufti have recourse to the Balha again, and pay a large tribute togberconfirmed in his dominions. "isIt is not to be imagined, thátall this is as foon done as faid; for these disputes and proceffes vlast sometimesd for two or three generations. Such of the Arab Princes as are most powerful, are most carefled by the officers of the Borte; who being liable to be removed, take cate to behave in such manner towards these princes, that in cale of neceffity they may have a safe retreat among them. :1.15

We are now arrived at the conclusion of the first volumes. the second iis come to hand, and next month, a view of its contents will be laid before our Readers. We make no apology for the length of this article; the work is new and curions is written in a foreign language, and the remarks, and explanation of Arabic words, which we have added, may be of use ato those who shall read Mr. Norden's performance in the original. 2 103 910997*7] on to the Digic hurt

osno

[ocr errors]

316 1951 9.O.

$$122.A 1710W Conclusion of the Philosophical Transactions, begun in aur laft,

Sud pio sisiting ni See page 271, feg) over

TH

Arts p2s Extracts.softw. Letters-to Thomas Holles, Esq; consyrid scerning the lato discoveries at Herculaneum.: 110 THESE Extraets are curious, bút‘Art. 23. is more to

Hour purpose, particularly Father Antonio's method of unfolding the paper fcrolls lately discovered in the fame fub terráneous city 5 S Vos ! WOHS 1713013 0719,*

This Friar, who is a writer at the Vatican, made a machine, with which, (by the means of certain threads, which

being gummed, stuck to the back pare of the papyrus, where • there was no writing)he begins, by degrees, to pull, while,

with a fort of engraver's inftrument, he loofens ones leaf • from the other, (which is the moft alfficult part of ally and . then makes a fórt of lining to the back of the papyrus, with . exceeding thin leaves of onion, (if I'miftake not) and with

fome fpirituous liquor, with which he wets the papyrus, by Hittle and little he unfolds 'it. All this labour cannot be well

comprehended without seeing. With patience superior to • what a man can imagine, this good Father has untolled a přetty large piece of papyrus, the worst preserved, by way. of trial. It is found to be the work of a Greek writer, and

is a small philosophic tract (in Plutarch's manner) on mufic; * blaming it as pernicious to fociety, and productive of foft? nefs and effeminacy. It does not discourse of the art of mufic. The beginning is wanting, but it is to be hoped, that

the author's name may be found at the end : 'it seems how& ever to be the work of a ftoic philosopher ; becaufe Zeno is • much commended. The papyrus is written acrofs in fo • many columns, every one of about twenty lines, and every • line is the third of a palm long. Between column and co& Jumn is a void fpace of more than an inch. There are now cunrolled about thirty columns, which is about half of the

whole; this roll being one of the largest : the letters are dif

tinguishable enough. Father Antonio, after he has loofened • a piece, takes it off where there are no letters, and places « it between two crystals, for the better observation; and then • having an admirable talent in imitating characters, he copies • it with all the lacunæ, which are very numerous in this

scorched papyrus ; and gives this copy to the Canon Maz• zocchi, who tries to fupply the loss, and explain it. The • letters are capital ones, and almost without any abbreviation. • The worft is, the work takes up fo much time, that a small

quantity of writing requires five or fix days to unroll, fo • that a whole year is already consumed about half this roll. • The lacunæ, for the most part, are of one or two words,

that may be supplied by the context. As soon as this roll is « finished, they will begin a Latin one. There are some fo « voluminous, and the papyrus fo fine, that unrolled, they

would take up an hundred palms space. They tell me, that & some of the Latin ones are in a running hand; which con. firms the opinion of the Marquis Maffei, " That the cha« racter by us abfurdly called Gothic and Lombard, is the 1" antient running hand corrupted by time.” However, I " have not seen any of these last. The curiosity of these pa• pyri is, that there is no little staff of wood, on which they were rolled.

Lieto

's • Thus have I told you all that I know concerning these

6

• papyri.

.We

may

comfort ourselves, that the affair is in good hands, being under the care and conduct of fo learned an

antiquarian, as the Canonico Mazzocchi, and of this able 6 and adroit Father Antonio.'

Dj Clinics

22

[ocr errors][merged small][ocr errors]
[ocr errors]

Art. 25. Letters of Henry Eeles, Esq; concerning the cause of

the ascent of Vapour and Exhalation, and those of winds; and of the general phenomena of the weather and barometer.

There have been several hypotheses proposed, in order to account for the ascent of vapours. Des Cartes was of opinion, that the particles of water, by the action of the sun, are formed into hollow spheres, filled with the materia fubtilis; by which means they are rendered lighter than an equal bulk of air, and consequently muft afcend in it. ** But as the materia fubtilis could never be proved, this theory gave no fatisfaction to those who would not admit of

any oce cult agent in accounting for the phænomena of nature.' InRead of the materia fubtilis, they had therefore recourse to the air, and supposed, that by the action of the sun on the surface of the water, the aqueous particles are formed into bubbles, filled with a flatus, or warm air, whereby they are rendered fpecifically, lighter than those of air, and therefore muft rise therein.

Those among the foreign philosophers, who maintain fire to be a particular substance, fuppose, that the rays of the fun, or the particles of fire separated from them, adhere to those of the water; by which means the aqueous particles are rendered lighter than an equal bulk of air, and consequently, by the laws of hydroftatics, must ascend in it,

Dr. Defaguliers, aware of the objections made to the above hypotheses, advanced another. He fuppofed, that the particles of water are so far feparated by heat, as to be without the fphere of each other's attraction, when they begin to repel each other, and by that means rise from the surface of the fluid in form of a vapour, or body of particles, which are at equal distances from each other; and becoming thus fpecifically lighter than the same bulk of airy particles, they will rife in the Auid body of air, till they come to that part of it which has the same gravity : where they will form what we call clouds, and will move with the current of the air in those regions.

Such are the principal hypotheses which have been advanced to account for the afcent of vapours; but all of them are liable to so many objections and difficulties, that some have, with very good reason, declared, they can think of no way of ac

counting for the rise of vapours, according to the received ? principles of philosophy *.

As

* See Rowning's System of Philosophy, Vol. I. p. 138. where the reader will find the feveral objections brought againit these hy

potheses.

As therefore, neither impulfion, rarefaction of the air, or any alteration of the watry particles, by expansion, is sufficient to account for the ascent of vapours, our Author has advanced a new hypothesis : that of electricity. He observes, that there is but one way of altering the specific gravity of the particles of vapour and exhalation, to render them lighter than air ;, which is, by adding to each particle a sufficient quantity of some Huid, whose elasticity and rarity are exceedingly greater than that of the air. That the electric fire is such, will be easily granted, but how far it is adapted to this purpose, can only be determined by experiments; by the help of which Mr. Eeles has found, that all fumes arising from fire, whether, blazing or otherwise, and all steams arising from boiling or warm water, and from all other fluids, and the breath of man, and of all other animals, and all the effluvia thrown off

by perspiration, are strongly electrified. And well known experiments have shewn, First, that desultory motion by

which it flies off from an electrified body to any number of (non-electrics, which are brought within the sphere of its

activity and affection, until it be equally diffused through all, potheses. Wih regard to that hypothesis which some have advanced, namely, That a body divided into minute particles, will ascend in a fluid fpecifically lighter than itfelf, it is too evidently false td need a refutation : for tho it be admitted, that the folidity of a globular particle increases as the cube, but the surface only as the {quare, of the diameter, and consequently very small bodies will have much larger surfaces, in proportion to their solid contents, than larger bodies will; yet this increase of furface, whilft the specific gravity remains the same, „will as much retard its afcent as its

s des Icent, and the proportion between the weight of a particle of one body or fluid (water for instance), and the weight of a particle of the same dimensions of another fluid (as air) will be the same as between the weights of larger masses of these fluids. Thus, leaf gold, for instance, immersed in a bason of water, will not rise to the surface; bct; on the contrary, fink to the bottom. Some tion, however, must be used in making this experiment ; for leafgold being so very tenuous, is apt to fold in immersing it in the water, and by that means confine some particles of air, which mus render it lighter than water, and consequently it will then rise to the surface. It is therefore necessary, after the gold is immersed, that these folds be entirely taken out, and the leaf pressed with the finger againit the bottom, till all the particles of air are discharged, and the water brought in contact with every part of its furface; after which it will no longer ascend to the surface of the water, but, on the contrary, if raifed to it, will immediately fink to the bottom by its own gravity,

e cau

[ocr errors]

Secondly, that the sphere of its activity is increased by heat. Thirdly, that this fre does not mix with air. Fourthly, that it intimately, pervades water, and many other bodies, covering their superficies to a certain distance; which dirtance is not in proportion to the bulk of the body electrified, but in proportion to the state of activity of the electrical

fluid.' To this our Author adds, that he found by expe riment, Fifthly, that this electrical Auid readily joins with

any fire which fumes, or rather with the blaze or fuines of any fire; but will not mix or fly off with the fire of red hot iron, or any other metal which does not fume.

? Now to thew that this electrical fire, or fluid, is the principal cause of the ascent of vapour and exhalation, we need only prove, that it attends all vapour and exhalation, domu

and that in such quantity, as is necessary to render them specifically lighter than the lower part of the atmosphere.

I shall not undertake to determine, by what cause vapour and exhalation are detached from their masses, whether by 20

the solar or culinary fire, or by the vibrations of the elec trical Ruid, rendered more active by those fires; tho I am 6 led to think the latter. But it is evident, that they are 6 emitted in exceeding minute distinct particles, and that

these particles must pass through that electrical Auid which surrounds the surface of the mass; and that, by that means,

they must be equally electrified with the mass; that is, they s must be covered with the electric fluid to as great a distance Sifrom their superficies as the mass is covered, which must alSways be in proportion to the state of activity of the electrical

Auid. In which ftate, when they have palled the surround“ing Auid, they must be repelled by it, and also repel each

other; and if each particle of vapour, and its surrounding fluid, occupy a greater space than the same weight of air,

they must be fitted to ascend till they come in equilibrium with the upper and rarer part of the atmosphere, where they must Aoat until their specific gravity is altered. As it

is very difficult to assign the magnitude of each particle of Yapour

and exhalation, and that of the surrounding fluid, 9 and to shew, that both taken together occupy a greater por tion of space, than the fame weight of air, we can only $b apply to experiment, to thew that it is poffible thar it may be so; and that will fhew, that in all probability it is 10; since it is evident, that every particle must be endued with a portion of this electrical fire, or Auid, and that there is not any other fufficient cause alligned for their ascending.

1

[ocr errors]
« AnteriorContinuar »