V tl 



of thefe, being gradually incruftated, were fwallowed up by 

 others which were larger, and more powerful, till at laft 

 they were all deftroyed, and fwallowed up, by the biggeft 

 Jolar vortex ; except foine few which were thrown off in 

 right lines from one vortex to another, and fo become 

 comets. See Cartesian PkUofophy. 



But this doftrine of vortices is, at bed, merely hypo- 

 thetical. It does not pretend to (hew by what laws and 

 means the celellial motions are really effefted, fo much as by 

 what meansthey pofriblymight,incafe it {houldhave fo plcafed 

 the Creator. But we have another principle which .iccounts 

 for the fame phenomena as well, nay better than that of 

 vortices ; and which we plainly find has an aftual exillence 

 in the nature of things : and this is gravity, or the weight 

 of bodies. 



The vortices, then, fhould be excluded from philofophy. 

 Were it only that two different adequate caufes of the fame 

 phenomena are mconfiftent. 



But we have other objeftions againft them. For, i. If 

 the bodies of the planets and comets be carried round the 

 fun in vortices, the bodies of the parts of the vortex im- 

 mediately invefting them, mull move with the fame velocity, 

 and in the fame direftion ; and befides, they muft have the 

 fame denfity, or the fame vis inertix. But it is evident, 

 that the planets and comets move in the very fame parts of 

 the heavens with different velocity, and in different direc- 

 tions. It follows, therefore, that thofe parts of the vortex 

 muft revolve at the fame time, in different direftions, and 

 with different velocities ; fince one velocity and direftion 

 will be required for the paffage of the planets, and another 

 for that of the comets. 



2. If it were granted, that feveral vortices are contained 

 in the fame fpace, and do penetrate each other, and revolve 

 with divers motions ; fince thofe motions mutt be conform- 

 able to thofe of the bodies, which are perfeftly regular, and 

 performed in conic feftions ; it may be afked. How they 

 ftiould have been preferved entire fo many ages, and not dif- 

 turbed and confounded by the adverfe at^ions and (hocks of 

 fo much matter as they mutt meet with ? 



3. The number of comets is very great, and their motions 

 are perfeftly regular, obferving the fame laws with the 

 planets, and moving in orbits that are exceedingly eccen- 

 tric. Accordingly, they move every way, and to all parts 

 of the heavens, freely pervading the planetary regions, and 

 going frequently contrary to the order of the figns ; which 

 would be impoffible, unlefs thefe vortices were removed. 



4. If the planets move round the fun in vortices, thofe 

 parts of the vortices next the planets, we have already ob- 

 ferved, would be equally denfe with the planets themfelves : 

 confequently the vortical matter contiguous to the peri- 

 meter to the earth's orbit, would be as denfe as the earth 

 itfelf : and that between the orbits of the earth and Saturn 

 muft be as denfe, or denfer. For a vortex cannot maintain 

 itfelf, unlefs the more denfe parts be in the centre, and the 

 lefs denfe towards the circumference : and fince the pe- 

 riodical times of the planets are in a fefqui.ilterate ratio of 

 their diftances from the fun, the parts of the vortex muft be 

 in the fame ratio. Whence it follows, that the centrifugal 

 forces of the parts will be reciprocally as the fquares of tlie 

 diftances. Such, therefore, as are at a greater diftance from 

 the centre, will endeavour to recede with the lefs force. 

 Accordingly, if they be lefs denfe, they muft give way to 

 the greater force, by which the parts nearer the centre en- 

 deavour to rife. Thus, the more denfe will rife, and the 

 lefs denfe defcend ; and thus there will be a change of 

 places, till the whole fluid matter of the vortex be fo ad- 

 jufted, as that it may reft in equihbrio. 



V s 



Thus will the greateft part of the vortex without the 

 earth's orbit have a degree of denfity and inaftivity, not 

 lefs than that of the earth itfelf. Whence the comets mult 

 meet with a very great rcfillance, which is contrary to all 

 appearances. Gotef. Prxf. ad Newt. Princ. The doftrine 

 of vortices, fir Ifaac Newton obferves, labours under many 

 difiiculties : for a planet to defcnbe areas proportional to 

 the times, the periodical times of the vortex fhould be in a 

 duplicate ratio of their diftances from the fun ; and for the 

 periodical times of the planets to be in a fefquiplicate pro- 

 portion of their diftances from the fun, the periodical times 

 of the parts of the vortex Ihould be in the fame proportion 

 of their diftances : and, laftly, for the lefs vortices about 

 Jupiter, Saturn, and the other planets, to be preferved, and 

 fwim fecurely in the fun's vortex, the periodical times of the 

 parts of the fun's vortex fhould be equal. None of which 

 proportions are found to obtain in the revolutions of the fun 

 and planets around their axes. Phil. Nat. Prir.c. Math, 

 apud Schol. Gen. in Calce. 



Befides, the planets, according to this hypothefis, being 

 carried about the fun in ellipfes, and having the fun in 

 the umbilicus of each figure, by lines drawn from them- 

 felves to the fun, do always defcribe areas proportion- 

 able to the times of their revolutions, which that author 

 fiiews the parts of no vortex can do. Schol. prop. ult. 

 lib. ii. Princip. 



Again, Dr. Keill proves, in his Examination of Burnet's 

 Theory, that if the earth were carried in a vortex, it would 

 move fafter in the proportion of three to two when it is 

 in Virgo than when it is in Pifces ; which all experience 

 proves to be falie. 



We have, in the Philofophical Tranfaftions, a phyfico- 

 mathematical demonftration of the impoffibihty and in- 

 fufBciency of vortices to account for the celellial phenomena 

 by Monf. de Sigorne. See No. 457. feft. vi. p. 409. 

 feq. 



This author endeavours to (hew, that the mechanical 

 generation of a vortex is impoffible ; that it has only an 

 axifugal, and not a centrifugal and centripetal force ; 

 that it is not fufficient for explaining gravity and its pro- 

 perties ; that it deftroys Kepler's aftronomical lav/s ; and 

 therefore concludes with fir Ifaac Newton, that the hy- 

 pothefis of vortices is fitter to difturb than explain the 

 celeftial motions. We muft refer to the differtation it- 

 felf for the proof of thefe affertions. See Cartesian 

 Philofophy. 



VORTICELLA, in the Linna-an fyftem of Zoology, a 

 genus of Vermes Infuforia, the charaAers of which are, that 

 the body is naked and contratlile, with a rotatory or whirl- 

 incr motion. Gmehn enumerates fifty-one fpecies. See 

 Vermes. 



VORTITZA, or VosTlTZA, in Geography, a town of 

 European Turkey, in the Morea, on the S. coaft of the 

 gulf of Lepanto ; 40 miles N.W. of Corinth. 



VOS, Martin de, in Biography, an eminent Flemilh 

 painter, fon of Peter de Vos, who was himfelf an artift and 

 member of the academy at Antwerp. He was born at Ant- 

 werp in 1520. His father initiated him in the art, but he after- 

 wards ftudied under F.Floris until he was twenty-three, and 

 then purfued the cultivation of his mind in Italy. The refi- 

 dence he made at Venice introduced him to tiie acquaintance 

 of Tintoretto, who not only inftruiSed him in the principles of 

 his praftice, but employed him to paint landfcapes in his pic- 

 tures. Hence De Vos became an admirable colourift, and 

 gained confiderable reputation and employment. He painted 

 portraits of the family of the Medici, and fome hiftorical pi&- 

 tures for them ; and after an abfence of eight years re- 



turned 



