228 



NA TURE 



{Jan. 20, 1876 



lection were also made by Dr. Mantell, Dr. MaccuUoch, 

 and Mr. Leonard Horner. 



It will be recollected that the Society was originated in 

 1807, at a time when mineralogy was a fashionable study, 

 or at least when collections of minerals formed part of 

 the " furniture " of the apartments of the Queen and many 

 of the nobility. Collections of shells and of fossils were 

 also fashionable, but they were valued only for their 

 beauty or their rarity, and not for any knowledge of nature 

 they afforded. For some time the young society seems to 

 have followed fashion. Indeed, the value cf fossil organic 

 remains as giving a clue to the consecutive sequence and 

 relative order of strata was then but just beginning to be 

 understood. It was not till the end of 1799 that the first 

 MS. table of the sequence from the Carboniferous beds 

 upwards was constructed, and no map of the strata of 

 England was published till 18 15. The earliest MS. cata- 

 logue of specimens belonging to the Society, begun in 1808 

 or 1809, is labelled "General Catalogue of Minerals," and 

 some of the early entries of organic fossils refer rather to the 

 rock in which the fossil is imbedded ; the presence of the 

 fossil being but casually noticed, such as " limestone con- 

 taining shells." These early collections of fossils illus- 

 trating the labours of the first geologists in using organic 

 remains to trace the chronological sequence of beds, and 

 to compile some chapters of the earth's history, have a 

 profound interest, laying as they did the foundations of a 

 science which has placed at rest many wild theories of 

 the origin of the earth, and has, too, proved to be of such 

 practical value. The first donation recorded is Feb. 5th, 

 1808, of specimens from St. Anthon's Colliery, Newcastle- 

 upon-Tyne, by the Right Hon. Sir J. Banks. It would 

 occupy too much space to mention all the collections that 

 the Society has preserved, but among the donors are the 

 well-known names of Sir Henry de la Beche, Sir Charles 

 Lyell, Greenough, Warburton, and Sir Woodbine Parish. 

 IVIcEnery's collection that first brought Kent's Cavern 

 into notice is there, and so is a splendid series of Daniel 

 Sharpe's " Brachiopoda." The old red sandstone fishes 

 presented by Lady Gordon Cumming are remarkable for 

 their beauty as well as for the extent of the collection. 



Many distinguished living geologists have private col- 

 lections of their own ; for example, the Earl of Ennis- 

 killen, Sir Philip Egerton, Prof. Prestwich, Mr. Searles 

 Wood, Dr. Bowerbank, &c., which fully explains why 

 their contributions are not so numerous as might be 

 expected from the valuable work they have done. Prof. 

 Phillips, though so energetic a worker, is not largely 

 represented in the museum, for firstly York, and after- 

 wards Oxford, had stronger claims on him. The same 

 remark applies somewhat to the claims of the Wood- 

 wardian Museum on Prof. Sedgwick. As illustrating the 

 geology of England generally, the Jermyn Street Mu- 

 seum and the British Museum are more useful, but as a 

 record of early geological work the museum of the Society 

 is unique. 



The rearrangement of the foreign collections has not 

 yet been completed, though it is in progress. Suites of 

 specimens £.re to be seen there from all parts of the 

 known world from which it has been possible for travellers 

 to send them. These foreign collections are, to some 

 extent, the result of contributions by officers in Her 

 Majesty's services. Central Africa is not represented, 

 but there are several collections from both coasts. For 

 the future it is intended to add to the British collection 

 only those specimens that are sent in illustration of papers 

 read to the Society, but foreign specimens will be received 

 as before. 



Among the treasures of the museum, besides the rocks 

 and fossils, there are the original drawings of Agassiz's 

 " Poissons Fossiles," presented by the Earl of Enniskillen, 

 the first manuscript geological map of England (1799), 

 and the first table of strata, by W. Smith (1799). 



The previous changes in the locality of the museum have 



been as follows : — In No. 4, Garden Court, Temple, the 

 first fixed habitation of the Society (June 1809), the collec- 

 tion was commenced. In June 1810 it was removed to 

 3, Lincoln's Inn Fields; in June 1816 to 20, Bedford 

 Street; in the autumn of 1828, to Somerset House; at 

 Somerset House it has remained till this last move to 

 Burlington House. 



CONDENSED AIR TRAMWAYS 



FOR some weeks the North Paris Tramways Com- 

 pany has been trying on the line from Courbevoie 

 to the Arc de I'Etoilc a new system of locomotion, 

 in which the motive power is compressed air. Some 

 details of M. Mdkarski's (the inventor) system are given 

 in the Revue Scientifique. It is capable of considerable 

 developments and of varied applications, since it has 

 solved in a very satisfactory manner the double problem 

 of the industrial production of air condensed to very high 

 pressures, and of the storage of the air in reservoirs in- 

 tended to discharge into a cylinder placed in any appa- 

 ratus whatever, at any distance from the condensing pump. 



The " Voiture Automatique " of M. M^karski is charac- 

 terised by the absence of an imperial and by a platform 

 in front and another behind. This car carries the reser- 

 voirs of condensed air, the apparatus for distribution, 

 and the cylinders. M. Mdkarski places under the truck 

 of the car the sheet-iron cylinders, which contain the 

 condensed air ; on the front platform is placed the distri- 

 buting apparatus which the engine-man works ; the two 

 cylinders are placed, as in certain locomotives, out- 

 side the framework, horizontally, and act directly, by 

 means of a crank, on the front wheels of the car. No 

 doubt this arrangement might be advantageously modi- 

 fied ; but the important point is the possibility of manu- 

 facturing compressed air in sufficient quantities to be of 

 use as a motive power. 



The condensing apparatus used by M. Mdkarski con- 

 sists of two pump-barrels of cast-iron, placed vertically, 

 communicating respectively with two horizontal pump- 

 barrels, in which move two pistons worked by a steam- 

 engine. This is, in reality, a double condensing pump, 

 the former bringing the air to the pressure of from ten to 

 twelve atmospheres, and the second raising the pressure 

 to twenty-five atmospheres. The pistons act upon a mass 

 of water which compresses the air directly and absorbs 

 by degrees the heat disengaged by compression. By an 

 ingenious contrivance the supply of water is continually 

 renewed, and the temperature thus kept down. But this 

 arrangement does not absorb a sufficient amount of the 

 heat disengaged, a difficulty which M. Mdkarski has met 

 as follows. The external air drawn into the pump raises 

 a valve constantly covered by a layer of water of several 

 centimetres ; besides, a large cast-iron tube, constantly 

 traversed by the air already condensed and the excess of 

 water, communicates with the two vertical pump-barrels ; 

 finally, the second pump is fitted with a tap by which the 

 heated water escapes. 



In M. Mdkarski's automatic car the compressed air is 

 stored, under the truck, in sheet-iron reservoirs or 

 cylinders. The total capacity is about 2,000 litres ; 1,500 

 litres serve as an ordinary supply ; 300 litres constitutmg 

 a reserve ; the remaining 200 litres are intended to serve 

 as a brake. The air is compressed in the cylinders to 

 the pressure of twenty-five atmospheres. On the line 

 from Courbevoie to the Arc de Triomphe, 7,500 metres 

 going and returning, the resistance is unusually great. 

 In one experiment the ordinary feeding cylinders con- 

 tained 1,500 litres of twenty-five atmospheres at depar- 

 ture, and the pressure, on arrival, was not more than four 

 and a quarter atmospheres. The expenditure had thus 

 been about 1,250 litres at twenty-five atmospheres for a 

 run of 7,500 metres, or 166 litres per kilometre. 



But unless it is possible to heat the air gradually 



