1877.] 



President's Address. 



437 



and consequently Greenland is an island. 3. This new tide contains a 

 sensible tertio- diurnal component of much interest. 

 The mean coefficients of the components are : — 



Semidiurnal tide =506 inches. 



Diurnal tide = 6*9 „ 



Tertio -diurnal tide = 4*5 „ 



The ' Challenger ' Expedition. — You will hear with gratification that 

 the Lords of the Treasury, after advising with your Council, have appro- 

 priated the munificent sum of ,£25,000 for publishing the biological 

 results of the voyage in a style and with a completeness worthy of the 

 Expedition and the nation. Adopting a course as wise as it is liberal, Sir 

 Wyville Thomson has, with the approval of your Council and the Govern- 

 ment, chosen for his collaborators the ablest specialists, irrespective of 

 their nationality. It is creditable to our country that, with but few 

 exceptions, it has supplied thoroughly competent and willing workers in 

 most of the departments ; and association with such foreign naturalists 

 as Agassiz and Haeckel cannot fail to be gratifying to themselves and 

 assuring to the public. I had the advantage of inspecting the Echino- 

 dermata in Professor Agassiz's charge in the Peabody Museum at Harvard 

 College, and of learning the progress he had made in the examination of 

 the vast body of materials entrusted to him. These, he informed me, far 

 surpassed Sir Wyville's estimate in number of species and of interesting 

 and novel forms ; and I was surprised to find that the whole had already 

 been sorted, that the greater part was named and ready for return to 

 Edinburgh, and that nearly a dozen exquisite lithographic plates of new 

 and rare forms were prepared for publication. 



Sir Wyville Thomson informs me that he is already far advanced 

 towards the publication of two quarto volumes, and that he estimates the 

 whole being completed in fourteen, of the form and size of the Philoso- 

 phical Transactions. 



Transit of Venus. — Sir George Airy has been pleased to inform me 

 that the inferences from the telescopic observations of the transit of 

 Venus, made in the British expeditions for records of that phenomenon, 

 under the superintendence of the Astronomer Royal, have now been pub- 

 lished — first, in response to an order of the House of Commons ; secondly, 

 in a more elaborate communication to the Royal Astronomical Society. 

 The number of districts of observation was five, but each of these included 

 a principal and some subordinate stations. The number of observers was 

 eighteen, and as some of them observed both ingress and egress of Venus 

 at the Sun's limb, the total number of observations was fifty-four. The 

 concluded value of equatorial mean solar parallax was 8"*754. The 

 calculation of the photographic records of the transit is advancing 

 rapidly. 



