CAMWL 



eraa a reaBarkaUe 

 Aod It mojel be remarked that 

 either 

 of prade- 



II. 'tpeak. of bioMalf a. the first who 

 i of UM BXWU a diameter depending upon her 

 "Ooi." says D.lambre. in ooe at his parcothceee, " U 

 - 1 - "--*, Aoatrat, at HewUus." Tfce sumn.ing up of thU 



But why, w may a*k, liu 

 has h. had more praisa to hi. 



CA8SINL 



Mi 



at laaat during their lira) 

 to praise, because he wu 

 tion constantly awake, because 

 such M bil guouion 



b. eeaploy*! for UM awe* put Ml 



ad Us long lilmnm and Uanae, being invited to France u a man 



bo couU not be don* withowt, the world early became accustomed 



r to thoae who had wiahad him to join them, 

 which UM monarch waa praised, and all tha 



S stowed upoat him want iodiractly to the kW He attributed 

 ritssssact) all lit dtocorartoa to Louis XIV.; ha waa tha 

 asaiuuuinii of UM court, so that it did not naad aa much as 

 he had to secure him more reputation than any other. All tha world 

 aalasteiiil fisaini'i disoovarias : Jupiter turned in h. 60m., Venus 

 la 43h. Mam, Mars in 24b. 40m. ; Saturn had four moons, which no 

 caw had aaaa till toea, and a medal bad been struck to commemorate 

 UM latter. la reality. thaM phenomena ware isolated novelties, infl- 

 arlaly aatinaa things, wtloh all astronomers are very glad to know, 

 but which could have btaa omitted without any result in the mnallet 

 decree prejudicial to UM progress of real astronomy. If we feel 

 ambus-toad to rrproach any on* it to not Caasini, but his contempo- 

 rartoa." Oa UM other hand, Lalande, an astronomer of real merit but 

 of e,riat waat of judgment, baa the following absurd exaggeration : 

 " Caiaini waa one of those rare man who seem formed by nature to 

 giva a new face to tha seianosa ; astronomy, augmented and perfected 

 in all its parta by UM discoveries of Cassini, underwent in his hands a 

 moat astoniahiog revolution. This great man waa the chief glory of 

 UM gl jry of Louis XIV. in this respect, and the name of Cassiui is 

 almost synonymous in Franc* with that of the creator of astronomy." 

 Oa which wa can only say, may every Lalande find a Delambre I 



The writings of Dominic Cassini are numerous, and a complete list 

 may be found la Lalande's ' Bibliographic Astronomique.' It is a 

 aiaaaiaplina, ao far aa it goes, of the accuracy of the character given 

 by DaJembre, that none of these writings are now sought after at con- 

 taiaiag matter of any bating value, except only the pure results of 

 :>. . 



J*s CASSISI, son of Dominic, waa born at Paris, February 18, 

 1677, aad at seventeen years of age wai thought of sufficient promise 

 to be received a member of the Academy of Sciences. He accom- 

 paaiad his father to Italy in 1695, and afterwards travelled in England 

 and Holland, where ha became acquainted with Newton, Flamteed, 

 . He auoaeaded his father at the observatory, was Msltre des 

 Cimiji.il, aad died April 1, 1750. Ho waa proceeding to his estate of 

 Taary, waaa. UM carriage was upset, and he became immediately 



Thar* to not much of brilliancy in the results of tho life of James 

 Caeaiai aa compared with thoae of his father, whom, on the whole, he 

 maeh rassuihliJ la Uu character of hii methodi of observing and 

 dododna> Ha was a batter mathematician, and devoted himself for 

 ^** part to fundamental pointa of astronomy, and to tho con- 

 atraotfoa of tablet, Hit separate writing! are not numerous ; tome 

 of thorn OB optMt by himself aad his brother (afterwards killed as 

 before stated) ware published in 191, being nothing but college exer- 

 rtoea, TW others ara, Da la Orandenr et de la Figure de la Terre/ 

 Paris, 1710; aad filament d'Astronomir,' IWi., 1740. 



Tha tret of thaw two works (a nitt to the Mem. Acad. Sci.' for 

 171> contains UM acoount of the continuation of Picard's arc of the 

 * f Dominie Cassini and U Hire In 1680, and recom- 

 I aad Jamas Ca-sini in 1700. On the results of this 

 oaecloded that the earth wai a spheroid 

 contrary both to theory and other 

 !* excited at tha time. The second 



* ** Wf fctaort aatroeonjy. It la aoeompaotod by a volume of 

 oaoaidorad at UM joint work of the father and 

 tiTS?** "*" ~PJW*<I * th. original edition became 

 ZnT' Hi? -*****?* ?T ." rro "* r diminish Ite value mate- 

 najly. Tba corraat edition to that of the Imprimerie Royalo. Paris. 

 Jth UM tear de4ys u UM trtte-paga. Fn>m this work wTaee that 

 ""-l!!^ 1 '*?* biamad, which to no graat matter of surprise, In 

 jy*hfc *>. awa to UM extent of declaring that the hypotheait 

 las) asMseecive |Nii|iagaliuB of light, which all UM worM knew to 

 |*oBa*mar, was in fast started, examined, and rejected by 

 "iPO**. ' ^rfi^A'* ^'^ *" A-^ny of Sclaiiom; 



** * J^rtiaa.p.it ab^^'d1,^ncUy^C..^ i i I1 a^d 

 * **t>trorfT upon tbt tubjcct, an<l that Dothinff but 

 ** Itsj*l40ti tw UM bypoio*Mu now known by UM DAOM of Iloemer 

 atroars to har, betoofd to Dotaiale C.^lnl. It appear, also that 



waa rather Copernksaii in life notions, but not very 

 strongly determined ; that be knew nothing, or next to nothing, of 

 UM system and writlturs of Newton (' Principis,' 1087; J. Cm-mis 

 'Astronomy,' 1740), which IM cites in two places once to endoavour 

 to explain the acceleration of Jupiter's motion, in another for obser- 

 vation* of a comet He knows nothing of Bradley ' discovery of 

 aberration (1787-88); but Delambre has forgotten when he adds that 

 he knew nothing of that of nutation, which was not published till 

 1747. He appears to be, like his father, a follower of Descartes, and 

 also, like him, to prefer graphical methods to calculation. His ideal 

 upon the theory of comets would have bean much the better for tha 

 study of Newton. Nevertheless, aa an observer, J. Caiaini was dis- 

 tinguished. His determinations of the times of revolution of the fire 

 satellites of Saturn then known are very exact : he first observed the 

 inclination of the orbit of the fifth (now the seventh) of them. He 

 improved the methods and tables of refraction ; determined very nearly 

 the variation of the obliquity of the ecliptic, and the length of the year 

 by comparison of a large number of equinoxes of his own and other*. 

 He left also a gr.-at number of good observations. Neverthele<s, it is 

 but justice to Ptoard and Roetner to remember, that both of the Ousinis 

 put together, distinguished aa they were, did absolutely nothing which 

 can now bring them to tha doily remembrance of the astronomer, 

 though their fame has surpassed that of the re-iuroutor of the 

 micrometer, and the inventor of the transit instrument. 



C.csiR FRANCIS CASSIHI, son of James, wai born at Paris, June 17, 

 1714. He is generally known by the name of Caasini de Thury, having 

 been the first to take a territorial appellation from the estate acquired 

 by bis father or gnndfuther. He accompanied his father during his 

 geodesical operations in 1738, and was received member of the Academy 

 at the age of 21. He succeeded his father a director of the observatory 

 and as maitre des comptes, and died September 4, 17S4, of small-pox. 

 His most remarkable labour is the large triiingnlation of France, pub- 

 lished in 1744, under the title of ' La Meridienne, *<;., verifier, to.,' 

 Paris. He nearly completed the large map of France, of which his sou 

 presented 124 sheets to the National Assembly in 1 789. He made a long 

 succession of observations at the observatory ; but these, though they 

 would have done credit to Dominic Cassini, were too late of thoir kind. 

 The time was past iu which a descendant of the first two Cassinia could 

 compete with tho rest of the world by bit hereditary means only. We 

 must refer to Lalande's ' Bibliographic ' for a list of his writings, and 

 to Delambre (' Histoire da 1'Astrouomie xviii. Si6cle ') for detail upon 

 hit astronomical observations. 



JOBN DOMINIC CASSINI, son of Cassiui de Thury, and most com- 

 monly known by his title of Count, was born at Paris June 30, 1748, 

 and died in the same city October 17, 1845. He is the first of hit 

 family who decidedly adopted the system of Newton, though the some 

 may perhaps be said of Casaini de Thury, from some isolated passage! 

 in his writings. He was elected member of the Academy in 1770, in 

 which year he published the account of a voyage made by order of the 

 king for trial of the chronometers of Le Koy. He was employed in 

 1787 with Hdchoin and Legendit) iu the operations for the junction of 

 the observatories of Paris and Greenwich by a chain of triangle*, lie 

 made repeated endeavours to induce the government to re-establish 

 the observatory upon a new footing and with large instruments. The 

 National Convention, apparently with the desire to force him to resign, 

 resolved in 17X3 that the observatory should be placed no longer under 

 the control of one person, but of four, who should take annual duty 

 in rotation. Of the four the Count Cassini was one, and the other 

 three were bis own pupils. To this he refused to submit, and resigned 

 hi* charge September 6, 1793. He received on order to quit the 

 observatory in twenty-four hours, and in the following year was 

 imprisoned for seven months. From that time bo abandoned astronomy 

 entirely, refusing either to take part in the great survey, or to belong 

 to the Bureau des Longitudes, or to tho Institute, though he entered 

 tha latter body under the empire. He fixed himself on his own estate, 

 and devoted himself to th duties of the Conseil of his department 



ALEXANDER QABRIKI. CASMNI, his son, the fifth of the name, was 

 born at Paris Hay 9, 1784, and began an astronomical career at a very 

 early age, but soon relinquished this pursuit for that of botany. He 

 was a judge of the Cour Koyale, and died of the cholera at Paris, 

 April 1, 1838. 



We have thus the history of the occupation of an observatory by 

 the members of one family for 122 years, and in spite of the deserved 

 reputation of all tho observers in question for talent and assiduity, it 

 must be asserted that tho hereditary system did not succeed. Delambre 

 remarks with some bitterness, that during the whole of the reign of the 

 Caesmls not " one little catalogue of stars " issued from the national 

 observatory. Picsnl had proposed the erection of large instrn; 

 and the observation of right osceneions and declination*. To tlii* 

 Dominic Caeaini was opposed, and in the usual course of tilings such 

 an error would have lasted for hi* life, and would have been repaired 

 by his successor. But when the first Cassiui was followed by a second 

 and a third wedded to the ideas of their common ancestor, there could 

 be no improvement; and tho consequence is that the observatory of 

 Greenwich, for the same period, bears away the palm from that of 

 Paris in actual e to astronomy. Had the National Convention 

 adopted the sound ideas of Count Cassini the case might hare been 

 altered, The erron of his predecessors appeared to be fully known 



