1887.] 



Pre side) it's Address. 



193 



Floras. The fact of widely dissevered localities for species, which 

 De Candolle found an insuperable obstacle to abandoning the doctrine 

 of multiple origin, has, in the hands of Hooker and A. Gray (as stated 

 by Bentham), afforded the most convincing proof of the genetic 

 relationship of the floras of which such species are components. 



In systematic botany, Hooker has perhaps had no rival since 

 Robert Brown. The ' ; Genera Plantarum," the joint work of himself 

 and his friend Bentham, and the "Flora Indica," to the completion of 

 which our colleague is devoting the leisure of a well-earned retire- 

 ment, form only as it were the head of an immense body of taxonomic 

 memoirs. 



Nor have his services to botanical science been confined to geo- 

 graphical botany and to taxonomy. His researches on various groups, 

 such as Welwitschia and others, deal in a masterly way with morpho- 

 logical problems of the highest interest and of extreme difficulty. 



While no one would attempt to minimise the commanding and 

 unique position of Mr. Darwin, the scientific historian of the future 

 will recognise how much the development of the modern theory of 

 evolution, from its first conception in the mind of Mr. Darwin, was 

 facilitated by the interaction upon one another of the work and minds 

 of Darwin, Hooker, and Lyell. It waS due to the earnest efforts of his 

 two friends that Mr. Darwin was induced to publish the first sketch 

 of the origin of species at all. And no one, had he been alive, would 

 have more cordially recognised than Mr. Darwin how vast an armoury 

 of facts the wide botanical experience of Hooker constantly placed at 

 his disposal in fortifying and supporting his main position. 



Of the two Royal Medals, it is customary, though it is not an in- 

 variable rule, to award one for mathematics or physics, and the other 

 for biological science. 



The medal which, in accordance w T ith the usual rule, has been de- 

 voted to mathematics and physics, has this year been awarded to 

 Colonel A. Clarke for his comparison of standards of length, and 

 determination of the figure of the earth. 



Colonel Clarke was for some twenty-five years the scientific and 

 mathematical adviser for the Ordnance Survey, and whilst acting in 

 that capacity he became known to the whole scientific world as 

 possessing a unique knowledge and power in dealing with the complex 

 questions which arise in the "science of geodesy. 



His laborious comparison of the standards of length, carried out 

 under General Sir Henry James, R.B., are universally regarded as 

 models of scientific precision. 



His determination of the ellipticity and dimensions of the earth 

 from the great arcs of meridian and longitude involved a very high 

 mathematical ability and an enormous amount cl labour. The con- 

 clusion at which .he arrived removed an apparent discrepancy between 



