1870.] 



President's Address, 



119 



Greenland, have given a new feature of interest to future explorations 

 within the Arctic Circle. The valuable memoir which Professor Oswald 

 Heer, of Zurich, has contributed recently to the Philosophical Transactions 

 (1869, Art. XIII.), has added much to the evidence contained in his pre- 

 vious papers of the existence, at that early period of the earth's history, of 

 a vegetation in some cases identical with, and in others scarcely differing 

 from, that which now lives and nourishes in the Temperate Zone — a vege- 

 tation comprehending oaks, planes, chestnuts, and even a Magnolia, the 

 leaves and fruit of which were found in the North-Greenland deposits. 

 Altogether, Professor Heer has identified no less than 137 species of the 

 Arctic flora of the Miocene age ; and he has moreover inferred, with great 

 appearance of reason, that at the same era vegetation of the same cha- 

 racter may have prevailed generally in lands within the Arctic Circle. The 

 anticipation of future discoveries of plant-remains, adding possibly largely 

 to the number of 137 species already recognized, must tend to give to 

 land-explorations and excursions an interest which was- comparatively 

 wanting to them when all that the explorer could anywhere hope to find 

 (other than the scanty, though in some respects beautiful, flora which the 

 rigours of the Arctic region at the present time still suffer to exist) was, at 

 most, the less attractive fossil remains of much earlier geological ages, to 

 the climatology of which less interest attaches than to that of the com- 

 paratively recent (however ancient) Miocene age. 



There have been in the past year two vacancies in the list of Foreign 

 Members of the Royal Society. The two gentlemen who have been elected 

 are Professor Joseph Antoine Ferdinand Plateau, of Ghent, and Professor 

 Anders Jons Angstrom, of Upsala. Professor Plateau has been an earnest 

 worker in the field of physical science for above forty years. His memoirs, 

 the titles of which (forty-six in number) are given in the fourth vo- 

 lume of the Society's Catalogue of Scientific Papers, .give evidence of 

 the completeness with which he has treated the subjects he has taken 

 up ; and many of his experiments are remarkable for their ingenuity and 

 originality. Questions in physical optics were the first to engage his at- 

 tention. In this branch of science his researches were confined to the 

 laws of visual appearances, including those relating to ocular spectra, the 

 duration of impressions on the retina, and irradiation ; and though some of 

 nis conclusions may have to be corrected, there is no doubt that in this special 

 department he has done more than any one of his predecessors or contempo- 

 raries. Another subject which has occupied him in his later years, and has 

 supplied the materials of eleven memoirs, concerns the figures of equilibrium 

 of a liquid mass without gravity. No one can contest the perfect origi- 

 nality of this series of investigations, or fail to admire the simple and 

 effective means by which he has carried out his experiments, and the saga- 

 city with which he has arrived at results which have formed a new starting- 



