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NA TURE 



[OcTOliliR 29. 1896 



In- Colonel Watson, R.E., on "Schools of Modern 

 OricnUil Studies"; by Mr. A. Montefiore Brice, on 

 "The Results of the Jackson-Harnisworth Expedition " ; 

 a course of three lectures, by Dr. J. L. W. Thudichum, 

 on "The Nature and Manufacture of Wine, with special 

 reference to Colonial Wines"; by Mr. J. Norman 

 Lockyer, C.IJ., F.R.S., on "How the British Empire 

 aids m Solar Inquiries" ; by Prof W. E. Ayrton, F R.S., 

 on "Sixty Years of Submarine Telegraphy"; by Mr. 

 .Spencer Pickering, F.R.S., on "The Woburn Experi- 

 mental P'ruit Farm." These lectures are open to Fellows 

 of the Institute, and to persons introduced by them. 



We warmly congratulate the Executive Council on the 

 new departures. The acknowledgment of the importance 

 of science on the part of the Governing Body comes none 

 too soon. 



Much remains to be done in this direction before the 

 Institute can be held to fill the place which many of its 

 best wishers consider it ought to occupy. 



FRANCOIS FELIX TISSFRAND. 



IT is impossible that we should have learnt the death 

 of an astronomer so eminent as M. Tisserand, the 

 Director of the Paris Observatory, without feelings of the 

 deepest regret, yet its terrible suddenness lends an added 

 note of pathos to the melancholy event. From the 

 report of the Paris correspondent of the 7>V«fj-, it appears 

 that on the evening of Monday, October 19, M. Tisserand 

 was present at the dinner celebrating the signing of the 

 marriage contract of the son of the late Admiral Mouchez. 

 On the following morning, apparently without the slightest 

 warning, M. Tisserand expired, the cause of death being 

 congestion of the brain. Astronomy, not only in France, 

 but wherever the science is studied, has thus sustained 

 a tremendous and irreparable loss, and especially will 

 sympathy be extended to the members of the staff of the 

 Paris Observatory, who, twice within a ie.\\ years, have 

 been deprived of their chief 



Frangois Felix Tisserand was born in the department 

 of Cote d'Or on January 15, 1845. He entered the 

 Normal School at Paris in 1863, and in 1868 gained his 

 Doctorate in Science. Although elected an agirgc in 

 1 866, he did not take up the duty of giving instruction, 

 but joined the staff of the Imperial Observatory as 

 assistant astronomer. In 1873, the astronomical service 

 was reorganised by M. Le ^'errier, and M. Tisserand was 

 nominated Director of the Toulouse Observatory, and 

 Professor of Astronomy in the Faculty of Sciences of the 

 same town. Subseciuently he became Professor of 

 Theoretical Mechanics at Paris, but was transferred, in 

 Mav 1883, to the chair of Mathematical Astronomy. In 

 this year he began that series of lectures at the Sorbonne, 

 the delivery of which has been attended with the happiest 

 results, for these lectures, given first as the deputy, and 

 subsequently as the successor to M. Puiseux, led 

 eventually to the preparation of that great work with 

 which M. Tisserand's name will ever be connected, 

 the " Traite de mecaniquecdleste." Though engaged for 

 some twenty years on this work, and necessarily much 

 occupied with official duties, his energy was not exhausted, 

 nor his services to science limited by this task, which 

 feu- men could have undertaken and brought to a suc- 

 cessful issue. In 1874, he accompanied M. Janssen to 

 Japan for the purpose of observing the transit of Venus, 

 and a few years later he was charged with the duty of 

 completing Delaunay's " Thdorie cle la Lune." Some 

 of the results of this close study of Delaunay's work 

 are shown in the third volume of the "Traite," in 

 the chapters entitled " Reflexions sur la theorie de 

 Delaunay." 



M. Tisserand's original memoirs and papers, the most 

 important of which were contributed, though not ex- 

 clusi\ely, to the Coinptes 7-ciidiis^ indicate a remarkable 



NO. 1409, VOL. 54] 



activity, and even an exceptional versatility, if that be 

 possible within the range of astronomical science. These 

 papers are fir too numerous to mention in detail, but 

 among them are ^•aluablc contributions on the theory of 

 interpolation, on problems presented by the minor 

 planets and meteors, on observations of sun spots, &c. 

 While at Toulouse, M. Tisserand made a collection of 

 e.\ercises in the infinitesimal calculus, which he published 

 in 1876. But the subject with which M. Tisserand's 

 name will always be associated is Celestial Mechanics. 

 The first volume of his " Traite de Mecanique celeste " 

 appeared in 1888 ; the fourth, which was understood to 

 be the last, has very recently been placed in the hands of 

 astronomers. This is not the place to attempt any 

 analysis of that great work, of which perhaps it is not 

 too much to say, that it will render a similar ser\ice to 

 the astronomers of the next century, that the work of La- 

 place did to those of the last. Herein will be found a 

 unique collection of methods, exhibiting great elegance in 

 the mathematical formulie, and everywhere enriched by 

 critical and historical reference to the original work of 

 other masters in particular departments. This work will 

 always stand as a worthy monument to the memory of its 

 author. 



In 1892, on the death of Admiral Mouchez, M. 

 Tisserand was selected to fill the position of Director of 

 the Paris Observatory. This appointment carried with it, 

 almost of necessity, that of the Presidency of the Comite 

 periiiaiicnt, to whom is entrusted the details connected 

 with the preparation of the Carte du Cicl. How loyally 

 he has struggled to give impetus to the scheme that his 

 predecessor had so much at heart, is sliown by the 

 various reports which he has presented to the Council of 

 the Observatory, and of which summaries have appeared 

 from time to time in N.VTURE. Under his auspices, a 

 bureau for the measurement of negatives has been estab- 

 lished or extended, additional instruments have been 

 provided for measurement, and energy and progress 

 have everywhere marked his short rule. He has 

 struggled manfully with the arrears of meridian observa- 

 tions, and had schemed a plan of publication reaching as 

 far as 1899. While thoughtful of the necessities of the 

 old astronomy, he has not been unmindful of the new, as 

 the free hand given to M. Deslandres, and the work 

 emanating from the spectroscopic department, abundantly 

 prove. Cut off at the early age of fifty-one, and after so 

 short an occupancy of the post of Director, he has per- 

 haps not had full opportunity to declare his capacity in 

 many directions, but he has done more than enough to 

 justify his selection to the important post he filled, and to 

 furnish a model to his successor. For he worthily up- 

 held the traditions of the institution ; and it is not saying 

 too much, although it is saying a very great deal, when 

 we affirm that he was a worthy successor in the line of 

 illustrious astronomers who had preceded him in the 

 control of the Paris Observatory. He had received an 

 abundance of honours, too long to fully enumerate, for 

 the scientific societies of all nations were proud to enrol 

 him among the list of their honoured associates. He was 

 decorated with the Legion of Honour in 1874, and four 

 years later succeeded Le X'errier among the full members 

 of the Academy. He was a member of the Bureau des 

 Longitudes, and held other positions of dignity and credit. 

 The St. Petersburg .'Academy voted him the Prix Schubert, 

 and the Royal Astronomical Society elected him a Foreign 

 Associate in 18S1. W. E. P. 



DR. HENRY TRIM EN. 

 'T^HE friends of Henry Trimen who saw him during 

 -'■ his last visit to England — a twelvemonth ago last 

 summer — would not be altogether unprepared for a 

 serious turn in the malady, or rather maladies, from 

 which he suffered ; yet the news of his death on the 



