Encyclopaedia Britannica, or, a Dictionary of arts, sciences, and miscellaneous literature : enlarged and improved. Illustrated with nearly six hundred engravings > Volume 13, MAT-MIC

Chap- V. M E T A P
Of called in (x) queftion), it can be confidered only as an
Morion, jnftrument employed uy Divine VViidom, as a chil-
fel or a law is employed by the -vviidom of the me-
203 chanic. _ . r
Xhi; iheory jqor ]et it be imagined, that this ancient theory oi
not incon- motion i3 in anv degree ineonfitlent with the mathe-
futent with matical prj[nt;ipl^s of Sir ifaac Newton’s aitronomy, or
with the calculations raifed from thofe principles.
Newton. Having founded his ailronomy on analogy between the
phenomena of projectile and planetary motions, he al-
figned the fame or iimilar forces exilting in nature as
•the efficient caufes of both. And indeed, both in
the aft of deriving his principles from the projectile
phenomena, and afterwards for the purpoie of apply¬
ing them to the planetary, it was neceilary to analyze
H Y S I C S. 635
the elliptical motion of the heavenlv bodies into a com- 0f
r A Mot-on.
pound oi two iimpie mutnms m light lilies, prouact*a
by the action of tlieie ditferent ioiees •, ana ^his might
alto be ufetul for the puipoles of teaching and detnon-
itraaon, juit as we finu it neceffary, in all parts of
fcience, to leparate what in nature is infeparable, tor
the convenience and affiltance of the under handing,
t he planetary motions, however, are very probably
limple ana uncompounded, tor no experiments can ue
tried in thofe diltant regions ; and the ahronom) of
Newion, which is only the application ol his maihe-
matical principles to their meniuiatn-n from their aoa-
logy to projectile motions, does not at all require that
the forces of gravitation and projection be aflignta as
their real exiltent caules (y). It is fufficient lor the
4 L 2 analogy,
matician than either of thefe pupils of the ancients-, and being like wife a man who on all fubjefts thought
L himfelf it may be worth while to lay before our readers a ftiort abihacl of Ins reafomng re peClmg the
origin of motion ^ His words are: “ Totum id quod novimus, cm nomen corpus indiaimus mini m le con-
t;net quod moms principium feu caufa efficiens effe poflit. Vis, gravitas, attratho, hujufmodi voces, utiles
funt ad ratiocinia et coraputationes de motu et corporibus metis led non ad mtelligendam fimplicem ipims motu.
nat iram vel ad qualitates totidem dittinHas defignandas. Attraaionem certe quod attmet, patet lilam ab Nei\-
tono adhiberi non tanquam qualitatem veram et phylicam, led folummodo ut hypothefm mathematical^
0 : et Jeibnitius nifum elementarem feu folicitationem ab impetu diftmguens, tatetur ilia entia non re p
fnveniri in rerum natura, fed abHraHione facienda effe. Similis ratio eft compohtioms et relolutionis vinum
11 >• rt.-rnm in nuafcunaue obhquas, per diagonalem et latere parallelogrammi. Hsec mechamees
e^aimputationi inferviunt : fed aliud eft computationi et demonftrationibus mathematicis infervire, ahud rerum
™tuZ Sere Rcvera corpu, *que prfevcral in utrovis liatu, vel motu, ve quKots. Il.a vero perleveiantta
naturam exhibere. i quam exiftentia eiufdem aftio diceretur. Ceeterum rehftentiam quam ex-
non magis dicen ^ • r,Ainnpm pffc finp-imus vana fpecie delufi. Revera enim iita refitientia
perimur in ftftendo coniia, utique no, tdem paituro, tuiife,
quam 2 ali„ principio impellatur. Aftfo et readio dicunlut- eife in corponbus ; nec
live corpus i. y- . ’ mechanicas. Sed cavendum, ne propterea fupponamus virtutem ahquam ;ealem,
incommode a ' mon . . - jp • ”s Etenim voces ilia; eodem modo intelligendae lunt ac vox attralao;
mathematica non autem quaiita, phyitca ; idem etiam de Uhs tn-
telligi debet, et ob eandem rationem. . remanebit nihil. Sed qualitates iftae funt ad motum
fcliiMt nulla aut attributum8 illis caufa efficietu vera eft, quas motura producat. Vocem autem ptolerre, et nthil
concipere, id demum lndl^.1;"' cooitantium : in iis autem potentiam ineflb corpora moveudi,
L^Tri pAprincipium motu,; particulare quidem et fubordinatum, quodque ipfun, dcpendeat, a pnmo et
M ^Tftt ” te^Tk contrario, qui — dfe principium mo.u, volunt, iententtam propr.a exponent.*
Inium preferunt, hfminumque omni tevo ^^^^“^ST^eret: quam quidem fententiam
feu mundum vifibilem, agitan et ammari a j".tn e» S £^ra effe, verum adhuc fvftema mundanum
(xl This we fax upon the received ..pinion, that there are things wholly incorporeal. The truth of the op.n.on
itfelf will be confidered in a fubfequent chapter. o- - ,c as tJ,e rm/ caufes of the phenomena.
(Y) Indeed Sir Ifaac himfelfvery far from pofinvely amgmng themjw Tne^ ^ ^ ;
The nurpofe for which they were introduced into to phb^ph-k* circmire, potefl et luna',
“ Eadem ratione qua projectile v. gravitatis in orbem flefl. poftet e. terram totam t ^