1895.] 



President's A ddress. 



117 



of the plates contained in these volumes ; and, though no expert in 

 the subject, I may be allowed to say that I believe nothing more 

 admirable has been hitherto given to the world in the way of illustra- 

 tion and representation of biological subjects. Of the maps, I may 

 confidently say that they are models of careful, accurate, and 

 elaborate work. Two volumes of the Report deal with the narrative 

 of the voyage, three volumes with the physics and chemistry of the 

 ocean, one volume with deep-sea deposits and geology, two volumes 

 with botany, forty volumes with marine zoology, and two volumes 

 are devoted to a summary of the scientific results. 



How highly the work of the " Challenger" expedition is appreci- 

 ated by those best qualified to judge of the merits of its results is 

 illustrated by the following words, spoken by Milne-Edwards at a 

 meeting of the International Congress of Zoology, held last Septem- 

 ber in Leiden : — " L'expedition du ' Challenger ' a porte des fruits 

 merveilleux. Ceux qui l'ont organise, ceux qui y out pris part, et 

 dont quelques-uns ne sont plus ici pour recueillir le prix de leurs 

 efforts, ceux qui en ont etudie les resultats, ont rendu des services 

 dont nous leur sommes profondement reconnaissants. Le monument 

 scientifique ainsi eleve par les savants anglais constitue un titre de 

 o-loire dont une nation a le droit d'etre fiere." 



The contributors to this gigantic Report are, for the most part, 

 natives of the United Kingdom and the British Colonies, but the 

 scientific men of nearly every civilised State are represented among 

 the authors. The British and foreign contributors are seventy-six 

 in number, and many scientific men whose names do not appear on 

 the title pages of the special memoirs have taken part in the physical 

 and chemical researches performed in connection with the work of 

 the expedition. Among the contributors w T e find the names of 

 Alexander Agassiz, Ernst Haeckel, P. Gr. Tait, Gr. 0. Sars, E. E. 

 Schulze, T. H. Huxley, Rudolph Bergh, A. v. Kolliker, A. Renard, 

 W. K. Brooks, 1ST. N. Polejaeff, Th. Studer, A. A. W. Hubrecht, W. 

 Dittmar, Sir William Turner, A. Giinther. Before the end of the 

 present meeting I shall have the pleasure of presenting to Mr. 

 Murray one of the Royal medals, which has been awarded to him by 

 the Council of the Royal Society to mark their appreciation of his 

 editorship of this great work and of his own scientific contributions 

 to it. 



In my Presidential Address of last year I took occasion to refer to 

 Lord Rayleigh's discovery that the gas which remains when oxygen, 

 vapour of water, and carbonic acid are removed from common air is 

 denser than nitrogen extracted from chemical compounds; and I was 

 then able to tell you of the consequent discovery that our atmosphere 

 contains a fifth constituent which is denser than nitrogen. This 

 discovery had been thoroughly established by Rayleigh, in association 



