Volume 2

A mathematical and philosophical dictionary: containing an explanation of the terms, and an account of the several subjects, comprized under the heads mathematics, astronomy, and philosophy both natural and experimental: with an historical account of the rise, progress, and present state of these sciences: also memoirs of the lives and writings of the most eminent authors. Both ancient and modern, who by their discoveries or improvements have contributed to the advancement of them ... With many cuts and copper-plates / By Charles Hutton.

  • Hutton, Charles, 1737-1823.
Date:
1795-1796
Catalogue details

Licence: Public Domain Mark

Credit: A mathematical and philosophical dictionary: containing an explanation of the terms, and an account of the several subjects, comprized under the heads mathematics, astronomy, and philosophy both natural and experimental: with an historical account of the rise, progress, and present state of these sciences: also memoirs of the lives and writings of the most eminent authors. Both ancient and modern, who by their discoveries or improvements have contributed to the advancement of them ... With many cuts and copper-plates / By Charles Hutton. Source: Wellcome Collection.

    148/818 (page 140)
    retarde-d by tbe refiftance of tlie air,' and the a£fion of gravity : and thus a top, once fet up in motion, only ceafes to turn round, becaufe it is relifted by the air, and by the fridtion of the plane upon which it moves. Thus alfo the larger bodies of the planets and comets preferve their progrefilve and circular motions a long time undiminifhed, in regions void of all fenfible refill- ance.—As body is pafllve In receiving its mmtion, and the diredtion of its motion, fo it retains them, or~ perfeveres in them, without any change, till it be acted upon by fomething external. ad I-.AW.—The Motion, or Change of Motion, is always proportional to the moving force by which it is produced, and in the direction of the right line in which that force is imprciTcd. If a certain force pro- duce a certain motion, s double force will produce double the motion, a triple force triple the motion, and fo on. And this motion, hncc it is always diredted to the fame point wn'th the generating force, if the body rvere in motion before, Is either to be added to it, as where the motions confpire ; or fubtradted from it, as when they are oppofite ; or combined obliquely, when oblique : being always compounded with it according to the de- termination of each. 3d L AW.'—Re-adfion is always contrary, and equal to aClion ; or the adtions of two bodies upon one an- other, are abvays mutually equal, and diredled contrary'- ways 3 and are to be eflimated always in the fame right line. Thus, whatever body preffes or draw's another, is equally prelTed or drawn by It. So, if I prefs a hone w'itli my hnger, the finger is equally prelTed by the Tone : if a horfe draw a weight forward by a rope, the horfe is equally oppofed or drawm back towards the weight; the equal teniion or ftretch of the rope hinder- ij^g the progrefs of the one, as it promotes that of the other. Again, if any body, by ftriking on another, do in any manner change its motion, it will itfelf, by means of the other, undergo alfo an equal change in Its own mo- tion, by reafon of the equality of the prefiure. When two bodies meet, each endeavours to perfevere in its Tate, and refifts any change : and becaufe the change which Is produced in either may be equally meafured by the adtion which it excites upon the other, or by the refiflance which it meets with from it, it follows that the changes produced in the motions of each are equal, but are made in contrary diredtions : the one acquires no new force but what the otlier lofes in the fame diredtioix; nsr does this laft lofe any force but what the other acquires ; and hence, though by their coHifions, rnotion paTes from the one to the other, yet the fum of their motions, eflimated in a given diredlion. Is preferved the fame, and is unalterable by their mutual adlions upon each other. In thefe adllons the changes are equal; not thofe, we mean, of tlie velocities, but thofe of the motions, or momentums ; the bodies being fup- pofed free from any other impediments^ For the changes of velocities, which are likewife ni'ade contrary ways, inafmuch as the motions are equally changed, are reciprocally proportional to the bodies or mafles. This law obtains alfo In attradtions. NAVIGATION, is the art of conducing a Tip at fea from one port or place to another. This Is perhaps the moft ufeful of all arts, and is of ihehighefl antiquity. It may be iinpoTible to fay who were the inventors of it; but it is probable that many people cultivated it, independent ci each other, who in- habited the coafls of the fea, and hadoccafion, or found it convenient, to convey themfelves upon the water from place to place ; beginning from rafts and logs of wood, and gradually improving in the flruclure and management of their vefiels, according to the length of time,\nd extent of their voyages. Writers however afcriFe the invention of this art to different perions, or nations, according, to their different fources of informa- tion. Thus, The poets refer the Invention of Navigation to Neptune, fome to Bacchus, others to Hercules, to Jafon, or to Janus, who it is fald made the firff flop.' Hillorians afcribe it to the Alginetes, the Phoenicians, Tyrians, and the ancient inhabitants of Britain. Some are of opinion that the firff hint was taken from the flight of the kite ; and fome, as Oppian (De Pifeibus, liH i) from the fiffi called Nautilus; while others afcribe it to accident; and others again deriving the hint and invention from Noah’s ark* However, hiftory reprefents the Phoenicians, cfpe- cially thofe of the capital Tyre, as the firff navigators, that made any extenfive progrefs in the mt, fo far as lias come to our knowledge ; and indeed it muff have been this very art that made their city what it was. For this purpofc, Lebanon, and the other neigh- bouring mountains, furnifning them with excellent wood for ffiip-bullding, they were fpeedily makers of a nu- merous fleet, with which conftantly haz^irding new na- vigations, and fettling new trades, they foon arrived at an incredible pitch of opulence and populoufnefs ; fo as to be In a condition to fend out colonip, the prin- cipal of which was that of Carthage ; which, keeping up their Phmnician fpirit of commerce, in time far fur- paffed Tyre itfelf; fending their merchant Tips through Hercules’s pillars, now the llraits of Gibraltar, and thence along the vveftern coafts of Africa and Europe ; and even, according to fome authors, to America itfelf. The city of Tyre being deftroyed by Alexander the Great, its Navigation and commerce w^ere transferred by the conqueror to Alexandria, a new city, well fituated for thefe purpofes, and propofed for the ca- pital of the empire of Afia, the conqueff of wliich ' Alexander then meditated. And thus arofe the Navi- gation of the Egyptians ; which was afterwards fo cul- tivated by the Ptolemies, that Tyre and Carthage were quite forgotten. E^>-ypt being reduced to a Roman province after tbe battle of Adlium, Its trade and Navigation fell into, the hands of Aiiguffus ; in whofe time Alexandria was only inferior to Rome ; and the magazines of the capi- tal of the world w'ere wholly fuppllcd with merchan- dizes from the capital of Egypt. At length, Alexandria itfelf underwent the fate of Tyre and Carthage ; being furprifed by the Saracens, who, in fplte of the emperor Heraclius, oyerfpread the northern coafts of Africa, &c '; whence the rner- chants being driven, Alexandria has ever fince been in a languiTIng ftate, tliough ffili it has a conliderable part of the commerce of the chriftian merchants traaing to the Levant. The fall of Rome and its empire drew along wnth it oot only that of learning and the polite arts, but that of Navigar.