401 



PERICECI. 



PERIPATETICS. 



-03 



27.1 711 430. H.-5, or 27 d -32166, the actual time of revolution of the 

 moon in the heavens. The satellites of Jupiter, Saturn, and Uranus 

 have revolutions round their primaries as follows : 



Japitcr'a First S. . 

 Second S. 

 Third S. . 

 Fourth S. 



Saturn's 



King 

 First 8. 

 Second S. 

 Third S. 

 Fourth S. 

 Fifth S. 

 Sixth S. . 

 Seventh* S. 

 Eighth S. 



d. h. m. 

 1 18 28 



3 13 11 



7 3 43 

 16 16 32 



10 32 

 U 22 38 



1 8 53 

 1 21 IS 



8 17 45 



4 12 25 

 \i 22 41 

 21 7 8 

 79 7 55 



d. 



1-7691 



3-5518 



7-1546 



16-6888 



0-4370 



0-9427 



1-3702 



1-8878 



2-7395 



4-5175 



15-9453 



21-2972 



79-3296 



The following are the old statements relative to the satellites of 

 Uranus, as given by William HeracheL Such an article as this is not 

 the place to enter upon the doubts relative to these bodies. 



d. h. m. d. 



Uranus's First S. 

 Second S. 

 Third S. , 

 Fourth S. 

 Fifth S. 

 Sixth S. 



Neptune's Satellite 



5 21 25 



8 16 58 



10 23 4 



13 10 56 



38 1 48 



107 16 40 



5 21 3 



5-8926 



( -7068 



10-9611 



13-4559 



38-0750 



107-6914 



i-8769 



The civil year is the tropical year, or the tune of revolution of 

 the sun from the vernal equinox to the same again. Owing to the 

 motion of the equinox [PBECESSIOS], this year, or SOS* 5 h 4S 49*7, or 

 365 <1 -2422414, is shorter than the actual revolution of the earth round 

 the sun, which is 365- 1 6 k 9" 9"6, or 365 d -2563612. Again, the anoma- 

 listic year, being that in which the earth moves from iU nearest point 

 to the sun to the same again, is 365 1 " 6" 13- 49"3, or 365 d -2595981. 

 The following is the list of the actual revolutions of the planets round 

 the sun, each to a tenth of a day, including the verified periodic 

 comets, so far as their times are known : 



De Vice's Comet 

 Brorsen's Comet 

 Biela's Comet 

 Fare's Comet . 

 Jupiter . 

 Saturn . 

 Uranus 



Halter's Comet 

 years. 



Days. 



1993-0 



2042-0 



2394-0 



2718-0 



4332-6 



10759-2 



30686-8 



5 to 78 



Of secular periods, the most important are, the revolution of the 

 moon's node, in 18-6 years ; of the earth's perihelion, from the vernal 

 equinox to the vernal equinox again (the latter also moving), or 

 21,000 years, and the revolution of the equinoxes themselves, in 

 26,000 years. 



PEKICECI (npiootoi), an old astronomical term for those who have 

 the same latitude, but opposite longitudes. 



PERIPATETICS (wtpmrnrucoi) is the name given to an ancient 

 philosophical sect. It was so designated from the circumstance of its 

 founder, Aristotle, being accustomed to deliver his doctrines while 

 walking in the grove of the Lyceum in the suburbs of Athens. [ARIS- 

 TOTLE, in Bioo. Div.] There is scarcely any department of human 

 knowledge of which the writings of Aristotle do not treat. It would 

 far exceed the limits of this article to give a full detail of his opinions. 

 Such of them only as characterised the school which he originated can 

 be referred to, and even these must be briefly noticed. They have 

 relation chiefly to his general physical and metaphysical principles. To 

 his system of logic, with the additions subsequently made to it by his 

 disciples, it is unnecessary particularly to advert. [OROANON.] 



Previous to Aristotle's time it was commonly supposed by those who 

 had speculated respecting the origin of the universe, that there is an 

 eternal substance from which bodies are made, and on which forms are 

 impressed, and to which the name of matter was assigned. This matter 

 was understood to have been always in motion, to consist of indefi- 

 nitely small particles, and to have been collected and united in bodies 

 by the agency of an intelligent principle. It was further supposed 

 that the original particles had certain properties by which they differed 

 from each other, and by which the constitution of the bodies which 

 they composed was determined. Empedocles and others taught that 

 there were four primary elements, which are the bases of all corporeal 

 forms ; Anaxagoras and his followers maintained that bodies exactly 

 represent the form of each of their constituent particles : while Plato 

 held that essential forms have an actual existence in the divinity, and 

 that by the union of these with matter the formation of bodies is 

 effected. 



Rejecting all these theories, Aristotle assumed the underived and 



Liicovered in 1848 by Lassell and Bond. 

 ARTS AXD SCI. DIV. VOL. Vt. 



independent existence of two opposite principles. But since such prin- 

 ciples by their contrariety would destroy each other, the existence of a 

 third was requisite. These he conceived to be matter, form, and 

 privation, the first two being the constituent principles of things, and 

 the last being accidentally connected with them. The first matter was 

 imagined to be entirely destitute of all qualities, to exist potentially, 

 and to be the subject in which forms are made to inhere. Form he 

 explained to be the essence of a thing, or that which constitutes it 

 what it is. How the first matter and form were brought into union 

 so as to produce bodies does not appear ; unless nature, the meaning of 

 which term, as employed by Aristotle, it is not easy to apprehend, 

 accomplishes the union. 



Aristotle distinguished causes into the material, the formal, the 

 efficient, and the final ; the first being that of which things are made, 

 the second that by which they are what they are, the third that by the 

 agency of which anything is produced, and the last the design of its 

 production. Having thus provided for the existence of substances 

 generally, Aristotle divides them into three classes : the eternal, as 

 the heavens ; the perishable, as the bodies of animals ; and the immu- 

 table nature, or prime mover, as it was otherwise called. This 

 prime mover, which occupies the place of God in his system, was 

 considered to be. an eternal, incorporeal, and simple intelligence, and 

 the original source of all motion, being itself unmoved. Its agency 

 extended directly to the first celestial sphere, and mediately through 

 similar inferior intelligences to the lower spheres, and by them to the 

 universe at large. 



Sensible bodies were divided by Aristotle into simple and compound ; 

 simple bodies being those elements which result from the combination 

 of primary matter and form, and compound bodies those which proceed 

 from elementary combinations. In bodies thus distinguished there 

 are certain active and passive qualities, which constitute their specific 

 difference, and by which they mutually tend to transform each other 

 into their own nature. In consequence of the action of the first 

 mover, whether direct or indirect, on matter, there is a continual 

 succession of dissolution and reproduction ; reproduction taking place 

 when the essence of a body is entirely changed, and only an augmenta- 

 tion or diminution when its accidental qualities undergo mutation. 



Such ban imperfect sketch of Aristotle's general doctrine of physics. 

 His opinions respecting man may be shortly summed up. The prin- 

 ciples of the soul and of animal life he thought to be identical, giving 

 them the common designation of entelecheia (KTe\exfio), or perfect 

 energy. The faculties of the soul he considered to be, the nutritive, 

 by which life is produced and preserved ; the sensitive, by which we 

 perceive and feel ; and the rational, by which we understand. The 

 sensitive faculty takes cognisance of external objects by means of 

 its organs, which are adapted to produce the various sensations of 

 sight, hearing, &c. The senses receive forms or sensible species in the 

 same manner as wax receives the impression of a seal. Fancy is the 

 perception which results from the immediate operation of the senses ; 

 while memory is derived from fancy, and is the effect of images formed 

 in the soul by the senses. The intellectual or rational faculty is of two 

 kinds, either active or passive. Passive intellect receives the form of 

 things, and is the seat of species. Active intellect is either simple or 

 complex : simple when it engages in the close apprehension of its 

 object ; complex when it combines simple conceptions so as to engender 

 belief. Intellectual action is theoretical when it contemplates what is 

 simply true or false, and practical when it determines what is good or 

 evil, and thus gives rise to volitions. 



Whether Aristotle believed in the immortality of the soul or not, 

 has not been clearly ascertained. From his notion that the soul is a 

 power externally transmitted into the body, it has been inferred that he 

 held it to be mortal, and that it ceased to have a separate existence 

 after the dissolution of the body. 



Aristotle's school in the Lyceum was continued for about twelve 

 years. In consequence of the hostility of his enemies, who accused 

 him of propagating impious tenets, he retired, soon after the death of 

 Alexander, to Chalcis, where he died. Before withdrawing from his 

 public labours however he appointed Theophrastus, of Eresus in 

 Lesbos, his successor in the chair. The opinions of Theophrastus 

 differed in some respects from those of Aristotle, but he taught with 

 great success, and was attended by about two thousand scholars. He 

 was followed consecutively by Straton of Lampsacus, Lycon, or Olycon 

 of Troas, Ariston of Ceos, and Critolaus the Lycian. With Diodorus 

 of Tyre, who came immediately after Critolaus, the uninterrupted suc- 

 cession of the Peripatetic school terminated, about the 140th Olympiad. 

 Among the early followers of the Stagirite, who did not fill the chair, 

 were several eminent philosophers. The most distinguished of these 

 were Dicsearchus, a Messenian, Eudemus of Rhodes, and Demetrius 

 Phalereus. 



The Peripatetic doctrines were introduced into Rome in common 

 with the other branches of the Greek philosophy by the embassy of 

 Critolaus, Carneades, and Diogenes, but were little known till the time 

 of Sylla. Tyranuion, an eminent grammarian, and Andronicus Rliodiua, 

 were the first who brought the writings of Aristotle and Theophrastus 

 into notice. The obscurity of Aristotle's writings tended much to 

 hinder the success of his philosophy, but it nevertheless soon gained a 

 considerable number of supporters. During the reign of the Csesars, it 

 acquired all its ancient influence ; and till the time of Ammonius, the 



D D 



