July 29, 1875] 



NATURE 



257 



circumstances for observation on more than one occasion, 

 yet entirely escaping detection, so that the mere fact of a 

 single observer only having seen a comet, is hardly a 

 sufficient argument against its existence. The late Prof, 

 d' Arrest even thought it worth while to submit the re- 

 puted observations of the D'Angos-Comet of 1784 to 

 further calculation, notwithstanding Encke's well-known 

 investigation in the " Correspondance Astronomique " of 

 the Baron de Zach, and we may have something to say 

 on this subject in a future column. Not having seen any 

 reference to " Stark's comet " in English astronomical 

 works, we have given the particulars recorded of it here. 



The Great Comet of 1843. — There was some doubt 

 at the time, from the difficulty attending the determina- 

 tion of the orbit of this extraordinary body upon the 

 European observations, whether it had transited the sun's 

 disc on the day of perihelion or not. The definitive orbit 

 calculated by a most complete investigation by the late 

 Prof. Hubbard, of Washington, shows that a transit did 

 actually take place on the evening of February 27, Green- 

 wich time, and might have been observed in Australia. 

 In next week's " Astronomical Column " we shall give the 

 particulars of this interesting phenomenon, and reproduce 

 Hubbard's elements with some inferences drawn from 

 them, 



D'Arrest's Comet in 1877.— The mean motion of this 

 comet at the last appearance in 1870, determined by M. 

 Leveau from an elaborate calculation of the perturba- 

 tions in the two preceding revolutions, would bring this 

 comet into perihelion again on April 17, 1877. The effect 

 of planetary attraction in the present revolution being 

 comparatively small, if we take this date for perihelion 

 passage, the computed path is not likely to differ ma- 

 terially from the true one. It is as follows : — 



T^^ p T^ Distance. 



^•^■^- from Earth. 



loo'6 ... 2"03 

 97-2 ... 1-94 

 93-2 ... 189 

 89-2 ... 1-89 

 857 ... 1-90 

 It would appear from this track that the only chances of 

 observation will be with the aid of powerful telescopes in 

 the southern hemisphere. At the last return the comet 

 was excessively faint, and was only detected at a few of 

 the European observatories. 



THE INTERNATIONAL GEOGRAPHICAL 

 EXHIBITION 



THE idea of holding an International Geographical 

 Exhibition at Paris, the opening of which we 

 announced last week, in connection with the Geographical 

 Congress which opens in a day or two, was a happy one, 

 and has so far been fruitful in results. The catalogue of 

 articles exhibited covers about 450 octavo pages, and the 

 daily number of visitors reaches thousands ; last Sunday it 

 was 12,000, including the Sultan of Zanzibar, and other 

 visitors of all ranks and classes of society. No better 

 method could have been adopted of showing the advances 

 made in geography in recent years ; how from being a 

 mere record of " hairbreadth 'scapes by flood and field," it 

 has become a complicated science, or rather meeting- 

 ground of all the sciences ; for, as the equipment of and 

 instructions to the English Arctic Expedition show, it re- 

 quires the aid of all the sciences to do its work well, and 

 in return carries contributions back to them all. We have 

 no doubt that the great majority of the visitors to the 

 Exhibition will be astonished that geography has so many 

 and so varied apparatus and results to show, and we hope 

 that the Exhibition and Congress will be the means of 

 awakening in France, as well as in other countries, an 

 increased interest in geography, lead to its being raised to 



a higher platform in education, and to its being taught in 

 a more comprehensive and more scientific way than 

 hitherto. No doubt this will be but the first of a series of 

 such exhibitions and congresses, though probably not 

 annual, and we hope that the next one will be held in 

 London. We think they are well calculated to give a 

 strong stimulus to the scientific study of geography. 



The arrangements of the Paris Exhibition make it 

 accessible to all classes, the price of admission in some 

 cases being as low as a penny. The articles are arranged 

 mainly according to countries, Britain occupying but a 

 comparatively narrow space in the catalogue. While 

 Russia has 42 pages, Sweden, Norway, and Denmark 

 about 40, Holland 30, Austria and Hungary 44, Great 

 Britain and her Colonies cover only 9 pages. Even Ger- 

 many has only 12 pages allotted to her. These apparent 

 anomalies no doubt arise from some imperfections in the 

 preliminary arrangements, and are probably to be looked 

 for in first attempts of this kind ; no doubt the organisers 

 of the next Geographical Exhibition will profit by the 

 defects of the present, and have one complete all round. 



As our readers are aware, the objects exhibited are 

 classified into seven groups ; an indication of what is 

 included in each group will convey some idea of the 

 nature of the objects exhibited, as well as of the compre- 

 hensive nature of modern geography. 



Group I., Mathematical Geography, Geodesy, and To- 

 pography, includes of course instruments of practical 

 geometry, surveying, topography, geodesy and astronomy ; 

 tables of projection and calculation, maps according to the 

 various systems of projection, sidereal maps, maps of 

 triangulation, maps showing the curves of magnetic decli- 

 nation, &c. In the second group, that of Hydrography 

 and Maritime Geography, is included a great variety of 

 instruments besides those used on board all sea-going 

 ships ; there are dredging and sounding apparatus with 

 specimens of what is brought up from the sea-bottom, 

 sounding thermometers and charts, and publications of 

 various kinds. The third group is an interesting one ; 

 it includes Physical Geography, General Meteorology, 

 General Geology, Botanical and Geological Geography, 

 and General Anthropology. These are illustrated by in- 

 struments used in the observation of the principal meteoro- 

 logical phenomena, by maps, atlases and globes repre- 

 senting the essential facts belonging to the domain of 

 Physical Geography, Meteorology, and the other sciences 

 referred to, as well as publications bearing upon them. In 

 group IV., that of Historical Geography, History of 

 Geography, Ethnography, and Philology, are included, 

 works and MSS., ancient and modern, bearing on these 

 subjects, ancient globes and maps, antiquated instru- 

 ments, ethnographic collections, and dictionaries of geo- 

 graphy. 



As might be expected, the fifth group. Economic, 

 Commercial, and Statistical Geography is a large and 

 varied one ; it includes works and maps bearing on popu- 

 lation, agriculture, industry, commerce, ways of commu- 

 nication, ports, colonisation, emigration, &:c., plans and 

 models of bridges, tunnels, railways, routes, telegraph 

 lines ; new apparatus for piercing rocks, manufactures 

 or mineral objects pecuhar to any country, collections of 

 all kinds of commercial products, machinery used in 

 manufactures of such products, produce and apparatus of 

 deep-sea fishing, &c. Group VI., Education and the Dif- 

 fusion of Geography, includes of course works, maps, 

 charts, globes, models and instruments of various kinds, 

 and deserves the attention of all engaged in education. 

 Group VII. comprehends Explorations, Scientific, Com- 

 mercial, and Picturesque Voyages, and, as might be 

 expected, includes a great variety of objects. There are 

 astronomical, topographical, meteorological, and photo- 

 graphic instruments of various kinds ; collections of 

 every kind bearing on voyages of exploration, including 

 cooking apparatus and drugs ; native implements and 



