p 



Nov. 27, 1873] 



NATURE 



69 



frogs and toads, the whole Eft order is unknown in those 



regions. 



Our question "What is a Frog?" has now been some- 

 what further answered ; but it cannot be completely so 

 until the organisation of the animal has been more fully 

 surveyed, and not only the relation of the frog to other 

 Batrachians thus more clearly seen, but also the relations 

 and affinities borne by the several orders of Batrachians 

 and by the wliole class to the other orders and other 

 classes of the Vertebrate sub-kingdom. 



Accordingly, we have now to make an acquaintance 

 with more than those obvious and external characters 

 which are found in the Frog, and to penetrate into its inner 

 anatomy, surveying successively its bony framework and 

 the various parts and organs which subserve the several 

 actions necessary to its continued existence. 



At the same time the more noteworthy resemblances 

 presented by the Frog to other creatures will be pointed 

 out. Thus we shall become acquainted with the relations 

 existing first between the Frog and other members of its 

 order ; secondly, between the members of its order 

 {Aiiouni) and its class fellows — /.(■. other Batrachians ; 

 thirdly, we shall comprehend the degree of relationship 

 existing between the Batrachia and the other classes of 

 the Vertebrate sub-kingdom ; and fourthly, we shall come 

 to recognise certain singular resemblances which exist 

 between the various groups of Batrachians (the Frog's 

 order of course forming one), and some of the orders into 

 which other vertebrate classes — especially the class of 

 Reptiles — have been divided. 



The skeleton of the Frog, both external and internal, 

 naturally comes first as the support and foundation of the 

 other structures. The in'ernal skeleton ipr c-iido-ske!t-ton) 

 will include the bones of the head, /.c. the skull, back- 

 bone (already referred to), and the bones of the limbs. 

 The external skeleton {exo-skeletoii) will consist of the 

 skin only. 



St. George Mivart 



( To be continued?) 



ASTRONOMICAL ALMANACS* 



V. — The "Connaissancc des Temps" under the continued 

 direction of the old Academy 



LET us return to the Connaissancc des Temps of the 

 old Academy. 

 Jeaurat, who succeeded Lalande in 1775, adopted exactly 

 the same principles as the latter ; he, however, extended 

 considerably the ephemerides of the moon, giving its de- 

 clination for every six hours, to facilitate the calculation of 

 the altitude, when at the same time only the distance could 

 be observed. Mechain succeeded Jeaurat in 178S ; he 

 followed the example of his two predecessors, and like 

 them, continued to take from the " Nautical Almanac " 

 the distances of the moon, which Maskelyne had the 

 kindness to send him even in manuscript. 



Moreover, besides the ephemerides and the lunar dis- 

 tances, the Connaissauce des Temps still contained obser- 

 vations, memoirs on various astronomical topics, an 

 abridged notice of new books likely to be of interest to 

 astronomers and navigators, and a brief history of astro- 

 nomy during the past year, due to the skilful and well- 

 informed pen of Lalande. This state of things continued 

 until 1794, the year when iNIechain left Paris, to take part 

 in the meridian work. Soon after, the suppression of the 

 academics having dispersed the astronomers, the Con- 

 iiaissduee des Temps for 1795 was compiled and published 

 by the temporary Commission of Weights and Measures. 

 Finally, on June 25 of the same year, 1795, the publica- 

 tion of this work was placed under the eminent direction 

 of the Bureau des Longitudes. Here we may conclude 



* Continued from vol. viii. p. 531. 



the first part of our account of the Connaissancc des 

 Temps — a work at first completely independent, then 

 published with the approbation of the Academy, which 

 included at the time nearly all those who were occupied with 

 astronomy ; and afterwards entrusted to the care of the 

 Bureau des Longitudes, a commission which still con- 

 tinues to^be charged with its publication. 



VL The " Connaissancc des Temps " under the Bureau 

 des Longitudes 



The first care of the Bureau was to entrust one of its 

 members with the publication and direction of the Con- 

 naissancc des Temps, thus showing, from the first, the 

 true course which ought to have been adopted from the 

 beginning, that a work of this kind demands strictly 

 personal superintendence. Its choice fell upon Lalande, 

 then Astronomer of the Observatory of F Ecole Militatre. 

 As to the calculations, however, the superintendence of 

 this astronomer was more nominal than real ; he was 

 occupied mainly with the Additions which he had com- 

 menced in 1760, and towards which the bent of his 

 mind, — " more of a collector than an inventor " — 

 carried him. Thanks to the great quantity of material 

 which he had acquired, he made of these additions 

 a work really useful, for at this time periodic scientific 

 publications were very rare. His Journal d' Astronomic 

 (history of astronomy during the preceding year), contains 

 a mass of information of great value, even at the present 

 day, to all who take an interest in the history of the 

 science of astronomy. 



As to the calculations, they were made partly by 

 Bouvard, whom Laplace had appointed adjoint to the 

 Bureau des Longitudes, and partly in the bureau of the 

 Cadastre, under the direction of Prony, its chief. It wa' 

 in the office of this celebrated engineer that the distance, 

 of the moon from the sun and from the principal stars 

 were calculated, distances which ceased from that time to 

 be taken from the Nautical Almanac. Let us, however, 

 add, that up to the year 1 8o5 the greater part of the 

 other calculations of the Connaissancc des Temps were 

 drawn from the Nautical Almanac, " with the view," 

 according to the preamble, " of accelerating the publica- 

 tion." Despite this assistance, nevertheless, this work 

 appeared only about a year and a half or two years in 

 advance ; it was then, at that time, completely useless to 

 navigators who had to make a long round. The atten- 

 tion of the Bureau des Longitudes was not however turned 

 in this direction. Its president was then the illustrious 

 Laplace, one of the glories of the mathematical sciences, 

 and who first knew how to deduce from the great dis- 

 covery of Newton, all the consequences which it was 

 calculated to yield. 



Pierre Simon Laplace was born March 23, 1749, of a 

 family of poor farmers of Beaumont-en-Auge (Normandy, 

 CalvadosX It is not known where he got the elements 

 of his education, for when later he was raised to the 

 highest honours, he had the weakness to wish to conceal 

 his humble origin. Appointed in 1770, on the recom- 

 mendation of d'Alembert, Professor of Matlvematics at 

 I' Ecole militaire of Paris, he became in 1772 adjoint 

 member of the Academy of Sciences, next succeeded 

 Bezout as examiner of the pupils of the royal corps of artil- 

 lery, and in 1785 was made titular Academician. During 

 this time, his beautiful memoirs on which he founded his 

 Mecanique celeste, succeeded each other almost without 

 interruption. Finally, in 1795, he was nominated presi- 

 dent of the Bureau des Longitudes, a position which he 

 held till his death, March 5, 1827. 



Lender his leadership the Bureau was occupied mainly 

 in perfecting and re-constructing the tables, by means of 

 which are calculated in advance the positions of the dif- 

 ferent stars. The tables of Delambre (the sun, Jupiter, 

 Saturn, Uranus and the satellites of Jupiter, 1792), of 

 Mayer (corrected by Mason, 1787), for the moon, of 



