ASTRONOMY. 



ASTRONOMY. 



670 



Riccioli . . 

 Mutus 

 Robcrval 

 De Billy . 

 Borelli . 

 Doerfel 

 Picard . 

 Lefevre . 

 Picard 



Hevelius . 

 Pound 

 Greenwood 

 Seth Ward 

 Aiizout . 

 Bouillaud . 

 Mercator, N. . 

 Mouton 

 Buot . . 



. 1671 

 . (1673) 

 . 1675 

 . 1679 

 . 1679 

 . (1680) 

 . 1682 

 . 1683 

 . 1684 

 . 1687 

 .(1687) 

 . (1689) 

 . 1689 

 . 1693 

 . 1694 

 . 1694 

 . 1694 

 . 1695 



Huyghens . . . . 1695 

 Richer .... 1696 

 Hooke .... 1703 

 Marquis de 1'Hopital . 1704 

 Duhamel . . . . 1706 

 Gregory, Dav. . . 1708 

 Roemer .... 1710 

 Cassiui, Dom . . . 1712 

 Cotes .... 1716 

 Leibnitz . . . 1716 

 Lahire, Phil. . . . 1718 

 Lahire, Gabriel P. . . 1719 

 Flamsteed . . .1719 



Keill .... 1721 

 Wren .... 1723 

 Wurzelbaur . . .(1725) 

 Newton .... 1727 



As we approach an age in which discoveries proceed rapidly, it would 

 disturb the order of time if we were to enumerate those of individuals 

 together. We shall therefore give the dates in chronological order of 

 the more remarkable phenomena which have appeared, and of the 

 principal accessions to the science, keeping, according to our original 

 plan, only enough to direct the attention of the reader to pointa worthy 

 of further reference. 



1660. Occurrence of a total eclipse of the sun which was observed 

 at Coimbra by Clavius. 



1667. Occurrence of an annular eclipse of the sun. 



1572. Apparition of a new Ktar in the constellation Cassiopeia. 

 Hageciug determines the apparent positions of -the new star of this 

 year by measuring its altitude on the meridian and noting the time of 

 observation. 



1.173. Thomas Digges proposes to determine the positions of the 

 1 Ixidieg by the method of corresponding altitudes. 



I. 1 ; 7 7. Apparition of a comet, the observations of which enabled 

 Tycho Brahe to demonstrate that cometary bodies revolve in the 

 regions beyond the moon. 



1581, or thereabouts, Galileo remarks the isochronism of the pen- 

 dulum. 



1690. An occultation of Mars by Venus witnessed by Moostlin. 

 (A doubtful observation.) 



1596. Kepler's ' Mysterium Oosmographicum,' containing fanciful 

 analogies between the orbita of the planets and the regular solids of 

 geometry. 



1 598. Occurrence of a total eclipse of the sun which was observed 

 in the north of Europe. 



1601. Occurrence of an annular eclipse of the Bun observed in 

 Norway. 



1603. Bayer's maps, in which the stars are first denoted by letters. 



1604. Kepler approximates more nearly to the law of refraction. A 

 new star appears in the constellation Serpentarius. 



1607. An apparition of Halley 's comet. 



1608. Telescopes invented in Holland by Lippcrhey, a spectacle 

 maker. 



1600. Galileo mode a telescope from a general description of a 

 magnifying instrument made by Lipperhey. He used a concave object 

 glaxs, Lipiwrhey a convex. Kepler publishes his work on Mars, in 

 whi'-h he establishes, from Tycho Brnhe"s observations, the elliptic form 

 of the orbit, and the proportionality of the areas to the times. These 

 are called Kepler 1 ! Jlrtt and ten/nil ' 



1610. Galileo announces the discoveries of Jupiter's satellites of 

 spots on the moon of nebula; of some new appearances in Saturn, 

 afterward* found to proceed from the ring phases of Venus. He also 

 discovers the diurnal libration of the moon, and that in latitude. 

 Harriot observes the spots on the sun. (This fact has only been 

 known from examination of Harriot's papers in the present century. 

 It ap|>ear3 he got telescopes from Holland.) 



1011. Lyncean academy founded. Galileo observes the spots on the 

 ML 



1614. Napier's invention of logarithms. 



1618. Prohibition of the theory of Copernicus by the Roman court. 



1617. Snellius measures an arc of the meridian at Leyden. This 

 waa the first done by trlanyulation ; b\it astronomical instruments were 

 nut yet sufficiently perfect to make this method much better than the 

 old one. 



1618. Kepler announces hit third law, that the squares of the periodic 

 times of the planets are in proportion to the cubes of their distances 

 f r< im tin; nun. Apparition of a great comet with a tail upwards of 

 100" in length. 



1619. Snellius discovers the law of refraction from one medium into 

 another. 



1626. Wendelinus determines the diminution of the obliquity of 

 the ecliptic. He also extended Kepler's law to Jupiter's satellites, and 

 ascertained the sun's parallax. 



1627. The ' Rudolphine Tables' published by Kepler, from the 

 observations of Tycho Bralie". 



1631. Gassendi first observed the transit of Mercury over the sun's 



disc ; he also measured the diameter of the planet. Vernier publishes 

 his invention of the instrument which bears his name. 



1633. Norwood measured the meridian from York to London, and 

 gave a more accurate value of the degree than his predecessors. 

 Descartes produced his system of vortices. Galileo is obliged to recant 

 his Copernican opinions by the Inquisition of Rome. 



1637- Horrocks suspects the long inequality in the mean motions of 

 Jupiter and Saturn. 



1638. Horrocks ascribes the motion of the lunar apsides to the dis- 

 turbing force of the sun, and adduces the oscillations of the conical 

 pendulum as an illustration of the planetary movements. 



1639. Horrocks and Crabtree first observed a transit of Venus over 

 the sun's disc. The former ascertained the diameter of Venus. They 

 were the only two who saw this particular transit. 



1640. Gascoigne applied the telescope to the quadrant, and a micro- 

 meter to the telescope. 



1646. Fontana observes Jupiter's belts. 



1647. ' Selenographia ' of Hevelius, in which the moon's h'bration in 

 longitude is announced. 



1650. Scheiner constructs a convex object-glass telescope. 



1651. A transit of Mercury observed by Shackerley, at Surat in 

 India. 



1652. A great comet visible in the heavens. 



1654. Huyghens completes the discovery of Saturn's ring. 



1655. Huyghens discovers a satellite of Saturn (Titan). 



1657. Academia del Cimento founded. 



1658. Huyghens made the first pendulum clock. 



1659. Huyghens, without being aware of what Gascoigne had done, 

 devises the original form of the micrometer as used on the continent. 



1660. Mouton applied the simple pendulum to observations of 

 differences of right ascension, and measured the sun's diameter very 

 correctly by it. 



1661. A transit of Mercury observed at Dantzig by Hevelius. 



1662. Royal Society of London incorporated. Cassini begins his 

 researches on refraction. Malvasia's improvement of Huyghens' 

 micrometer. 



1663. Gregory makes his reflecting telescope. 



1664. Hooke detects the rotation of Jupiter. 



1665. Cassini determines the time of rotation of Jupiter, and 

 publishes the first Tables of the Satellites. Hooke proposes to measure 

 the distance of the moon from the stars in her vicinity, by means of a 

 rete or divided cafe. 



1660. Cassini determines the rotation of Mars, and makes a first 

 approximation to that of Venus. Academy of Sciences founded at 

 Paris, and observatory first thought of and commenced in the following 

 year. Auzout applied the micrometer to the telescope without any 

 knowledge of Gascoigne. Newton first turned his attention to gravi- 

 tation. 



1867. Auzout and Picard applied the telescope to the mural quadrant, 

 without knowing that Gascoigne had preceded them. 



1688. Cassini's second Tables of Jupiter's Satellites. 'Cometo- 

 graphia ' of Hevelius. A great comet visible in southern latitudes. 



1669. Newton made his first reflecting telescope. 



1670. Mouton's first use of interpolations. 



1671. Picard and La Hire publish their degree of the meridian, 

 obtained by measuring from Paris to Amiens. Richer, in a voyage to 



! if, observes the shortening of the seconds' pendulum in approach- 

 ing the equator. Flamsteed begins observing at Derby. Cassini begins 

 the observations which led to his discovery of the inclination of the 

 lunar equator, and the coincidence of its nodes with those of the orbit. 

 Cassini discovers a satellite of Saturn (Japhet). 



1672. Cassini discovers a satellite of Saturn (Rhea). 



1673. Huyghens publishes his ' Horologium Oscillatorium,' in which 

 are found the first theorems on central forces and centrifugal force. 

 Flamsteed explains the equation of time. Picard, in the course of his 

 labours at the Royal Observatory of Paris, introduces the practice of 

 determining the positions of the stars by observing their altitude on 

 the meridian and noting the corresponding time. 



1674. Hooke revived the idea of attraction, but without assigning 

 any law, or connecting it with any observed facts. Spring watches 

 made under the direction of Huyghens, who was unacquainted with 

 what Hooke had already done in the matter. 



1675. Roemer announces his discovery of the velocity of light by 

 means of Jupiter's satellites. Greenwich Observatory founded. D. 

 Cassini discovers the division on Saturn's ring. Roemer recoguises the 

 advantages of the transit instrument for determining the right ascen- 

 sions of the stars. 



1676. Flamsteed commences his observations at the Royal Observa- 

 tory, Greenwich. 



1677- A transit of Mercury observed at St. Helena by Halley. 



1679. Halley published his Catalogue of Southern Stars, observed at 

 St. Helena. Appearance of the ' Connaissance des Terns.' 



1680. Flamsteed gives the law of the annual equation of the moon, 

 and corrects the tables accordingly. A great comet appeared in the 

 heavens. This comet is remarkable for having, on its passage of the 

 perihelion, approached nearer the sun than any other comet recorded 

 in history, with the exception of the great comet of 1843. It is also 

 Tnemorable for having conducted Newton to the important discovery 



