Volume 1

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.

  • Charles Hutton
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.

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    A C f ■’ V.' A C H C 24 ] according to tlie fmgle colour, or affemblage of colours, in the objecl ; and they continue for fome time after the eye is withdrawn, and give afalfe colour- ing to other objedls that are viewed during their conti- liuance. M, Buffon has endeavoured to trace the con- iicdtion between thefe accidental colours, and thofe that are natural, in a variety of inftances. M. d’Arcy con- trived a machine for meafuring the duration of thofe impreflious on the eye j and from the refult of feveral trials he inferred, that the effedf of the adlion of light on the eye continued about eight thirds of a minute. ddie lubjetl has alfo been confidered by M. de la Hire, and M, Aepinus, &c. See Mem. Acad. Paris 1743, 2nd 1765; Nov. Com. Petrop. vol. 10 alfo Dr. Prieilley’s Hill, of Difeoveries relating to Viiion, pa. 631. Accidental Point, in Perfpedtive, is the point in which a right line drawn from the eye, parallel to an- other right line, cuts the picture or perfpeftive plane. Let A B be the line given to be put into perfpedtive, C F D the pifture or perfpedlive plane, and E the eye : draw E P parallel to A B ; fo fhali F be the accidental point of the line A B, and indeed of all lines parallel to it, fince only one parallel to them, namely E F, can be drawn from the fam.e point E ; and in the accidental point concur or meet the reprefentations of all the pa- rallels to A B, when produced. It is called the accidental point, tq diftinguidi it from the principal point, or point of viewy wBere a line drawn from the eye perpendicular to the perfpedlive plane, meets this plane, and which is the accidental point to all lines that are perpen_iJicular to the fame plane. Accidental Dignities, and Dehilities, in AJirology, are certain cafual difpofitions, and affedlions, of the planets, by which they are fuppofed to be either ftrengthened, or weakened, by being in fuch a houfe of the figure. ACCLIVITY, the dope or lleepnefs of a line or plane inclined to the horizon, taken upwards ; in con- tradiftindlion to declivity, which is taken downwards. So the afeent of a hill, is an acclivity : the defeent of the fame, a declivity. Some writers on fortification ufe acclivity for talus : though more commonly the word talus is ufed to denote the Hope, wFether in alcending or defeending. ACCOMPANYMENT, in Mujjc, denotes either the different parts of a piece of mulic for the different inftruments, or the inlfruments themfelves which ac- company a voice, to fuffain it, as wHl as to make the mufic more full. The Accompanyment is ufed in recitative, as w^ell as in fong; on the ffage, as well, as in the choir, &:c.. The ancients had llkewife their accompanyments on the theatre ; and they had' even different kinds of inflruments to accompany the chorus, from thofe which accompanied the adfors in the recitation. The accompanyment among the moderns, is often a different part, or melody, from the fong it accompanies. But it is difputed whether it was fo among the an- cients. Organifls fometimes apply the word to feveral pipes w'hich they occafionally touch to accompany the treble ; as the drone, the flute, &c. ACCOMPT. See Account. ACCORD, according to the modern French mufic, is the union of two or more founds heard at the fame time, and forming together a regular harmony. They divide Accords mto perfed and imperfeB; and again into confonances and dijfonances, Accord is more commonly called Concord, which fee. Accord is alfo fpoken of the flate of an inflrument, when its fixed founds have among themfelves all the juflnefs that they ought to have. ACCOUNT, or Accompt, in Arithmetic, 8cc, a calculation or computation of the number or order of certain things ; as the computation of time, &c. There are various ways of accounting ; as, by enu- meration, or telling one by one ; or by the rules of arithmetic, addition, fubtradlion, &c. Account, in Chronology, is nearly fynonymoiis with flyle. Thus, we fay the Englifh, the foreign, the Ju- lian, the Gregorian, the Old, or the New account, or ftyle. We account time by years, months, Icc; the Greeks accounted it by olympiads ; the Romans,, by indidtions, luftres, &c. Acherner, or Acharner, in Afironomy, a ftar of the firfl magnitude in the fonthern extremity of the conftellatlon Eridanus, marked a. by Bayer. Its longi- tude for 1761, X 11° 55^ i 2nd latitude fouth 59° lA 4. ACHILLES, a name given by the fchools to the principal argument alleged by each fedl of philofophers in behalf of their fyflem. In this fenfe we lay this is his Achilles; that is, his mafter-proof: alluding to the flrength and importance of the hero Achilles among the Greeks. Zeno’s argument againft motion is peculiarly termed Achilles. That philofopher made a comparifon between the fwiftnefs of Achilles,and the flowmefs of a tortoife, pretending that a very fwift animal could never over- take a flow one that was before it, and that therefore there is no fuch thing as motion : for, laid he, if the tortoife were one mile before Achilles, and the motion of Achilles 100 times fwifter than that of the tortoife, yet he would never overtake it; and for this reafon, namely, that while Achilles runs over the mile, the tortoife will creep over one hiindiedth part of a mile, and will be fo much the foremoft ; again w’hile Achilles runs over this j^^r^h part, the tortoife will creep over the 100th part of that y^^th part, and will hill be this laft part the foremoil; and fo on continually, according to an infinite feries of looth parts: from which he concluded that the fwifter could never overtake the flower in any finite time, but that they mull go on ap- proaching