^5° 



NA TURE 



[July i i, 1901 



insects of the orders Lepidoptera and Coleoptera. Fifteen 

 coloured plates illustrate this \oIunie, amongst which we 

 may call special attention to that of a new lemur from 

 Madagascar, Propiihecus majori, drawn by Keulenians. 



The second volume (1895) is nearly of the same 

 character, and contains, amongst other rarities, a figure 

 of the very remarkable duck Salvadorina waigiouensis, 

 lately discovered in the little-known island of Waigion, 

 the last place, perhaps, in which one would have thought 

 of looking for a merganser. In this volume also will be 

 found a description of some very interesting remains of 

 the extinct gigantic bird of Madagascar {^-Epyo>-i?is) pre- 

 pared by Mr. C. W. Andrews, of the British Museum ; 

 also a beautiful figure (by Keulemans) of a new and 

 most magnificent bird of paradise, Astrapia splcndid- 

 issiina, based on a specimen in the Tring Museum 

 which is said to have come from the foot of the Charles 

 Lewis mountains in Dutch New Guinea. 



We neecf not recapitulate the contents of the following 

 five volumes, which, however, are all of great zoological 

 interest. But we may allude to some of the most extra- 

 ordinary novelties illustrated, amongst which are (in 

 vol. iii.) a very remarkable new Picarian bird from Mada- 

 gascar, Uratelornis chimaera. In vol.' iv. will be found 

 figured another new and extraordinary bird of paradise, 

 described by Mr. Rothschild as Loboparadisea sericea. 



In vol. V. are pictures of two beautiful new tanagers, 

 discovered by Mr. Rothschild's collector, Rosenberg, in 

 North-western Ecuador. 



In vol. vi. is given a figure of a new and gigantic tree- 

 kangaroo {De?idrolngits maximits) lately discovered in 

 Dutch New Guinea. This volume likewise contains an 

 elaborate essay by Mr. Rothschild on the kiwis or 

 apteryxes of New Zealand, with a chapter on their 

 anatomy by Mr. F. E. Beddard, F.R.S., illustrated by 

 numerous plates. 



In vol. vii. (igoo) will be found the conclusion of an 

 important monograph on the butterflies of the genus 

 Chara.xes and the allied forms, prepared by Mr. Roths- 

 child in conjunction with Dr. Jordan, and accompanied by 

 numerous illustrations, which was commenced in vol. v. 

 It will be evident, therefore, we think, that, as already 

 stated, Mr. Rothschild has selected a most appropriate 

 title for the organ of the Tring Museum, and has been 

 very successful in his search for the subjects to which its 

 pages are devoted. 



THE METRIC SYSTEM. 

 Le Systhne MHrique. By G. Bigourdan. Pp. vi-l-45S. 

 (Paris : Gauthier-Villars, 1901.) Price fr. 10. 



MG. BIGOURDAN, of the Astronomical Observ- 

 • atory of Paris, has published a work with the 

 object, apparently, of showing how leading a part France 

 has taken in the introduction and propagation of the 

 international metric system of weights and measures. 

 The book, however, tells one nothing new, for cannot all 

 it tells be found as to early history in " Base du Systeme 

 Metrique " (1S06, 1821) ; as to subsequent development 

 in the works of Barny, Saigey, Tarbe, Leoni-Levi, the 

 second report of the Standards Commission (1869), 

 &c. ; and as to latest scientific data in the Proc. Verb, 

 ci Trav. et Mem. du Bureau International des poids 

 NO. 1654, VOL, 64] 



et >nesures (Gauthier-\'illars, 1S75-J900)? Many of 

 these publications are, however, difficult to obtain, and 

 hence M. Bigourdan has met a want by putting together 

 under one cover all available information with reference 

 to the origin, construction and verification of metric 

 standards. 



In these days of advertisement some readers fight shy 

 of log-rolling works, of the dishing-up of old books 

 under new titles, of the re-editing of other men's labours, 

 and perhaps of the literature of metric propaganda 

 there has been enough. In the present work, however, 

 the temptation to advertise appears to have been avoided, 

 and the compiler has simply given, in a careful, concise 

 and exhaustive manner, the results of the labours of the 

 eminent chemists, physicists and mathematicians — as 

 Arago, Benoit, Berthollet, Bertrand, Borda, Broch, Cornu, 

 Delambre, Deville (H.), Faye, Fizeau, Foerster, Lagrange, 

 Lalande, Laplace, Lavoisier, Stas, Tresca, &c. — who have 

 made the metric system the only international system for 

 all purposes. 



The book contains thirty-three chapters, the first of 

 which deals with the weights and measures in use in 

 France previous to the revolutionary period, and to the 

 hypotheses of Bailly and Paucton with reference to uni- 

 formity. Then follow chapters referring to the proposition 

 of Talleyrand to the General Assembly of France in 1789 ; 

 to the decrees of that .Assembly in 1790 establishing a 

 new and uniform system of measurement ; and to the 

 establishment (under the Metric Convention of 1875) of 

 the Comite International des poids et mesures. This 

 Comite was thus one outcome of the original proposition 

 of 17S9— a remarkable outcome generally, seeing that it 

 changed the weights and measures of nearly the whole 

 of Europe, and swept away native and arbitrary metro- 

 logical systems which had been handed down from 

 primitive times ; systems embarrassing to scientific 

 progress, hurtful to commerce and a tax on intelligence. 



M. Bigourdan (p. 14) seems to say that in 1790 some 

 communication was made by France to England as to 

 the adoption of a new international base of measure- 

 ment. No such communication was, however, made 

 either through the Foreign Office or officially to the 

 Royal Society ; nor was England then invited to take 

 part in the establishment of the metric system. 



An interesting account is given by the author of the 

 founding of the Bureau International (Pavilion de 

 Breteuil, Sevres, pres Paris) ; of the construction of the 

 new international standard of the metre, and of the kilo- 

 gramme ; made of platinum (90 per cent.) and iridium 

 (10 per cent.) ; and which were in 1889 deposited at the 

 International Bureau, where they are still kept. An 

 account is also given of the verification of the etalons- 

 nationaux, or copies of the etalons-internationaux, which 

 have now been distributed to the high contracting 

 states who have joined the Convention of 1S75. The 

 national standard metre and kilogramme, which were 

 issued by the Comite to Great Britain, are referred to in 

 the Metric .Act of 1897. 



With reference to the determination of the length of 

 a linear measure, as the metre, by spectroscopic reference 

 to rays of light. Prof. Michelson and Dr. Benoit obtained 

 remarkable results in 1892-3. 



Reference is also made by M. Bigourdan to;.the re- 



