1872.] 



President's Address. 



29 



Pogson has shown that an annular eclipse is equally available.) I cannot 

 pretend now to describe all the characteristics of the four strata of the 

 Sun's atmosphere, or the evidence of their containing various terrestrial 

 components, or the proofs that they are in different states of temperature ; 

 nor can I describe the phenomena of the corona, or those in the neigh- 

 bourhood of the solar maculae. Much also has been done by spectroscopic 

 examination of the sun without eclipse ; and a spectroscopic society in 

 Italy has employed itself principally on that object. The Lords Com- 

 missioners of the Treasury have sanctioned the establishment, at the Royal 

 Observatory of Greenwich, of photoheliographic observations (to be 

 made, during the Transit-of- Venus Expedition, with the Kew Instru- 

 ment, by permission of your Council) and of spectroscopic observations : 

 the former system, it may be expected, will be in regular action 

 withia a few months ; the latter scarcely admits of being carried on 

 in official routine, but will be occasionally active. — Preparations are 

 far advanced for publishing a nearly complete report of the Eclipse of 

 1870 ; the observations of that of 1871 are not yet entirely collected. — 

 Nearly all the Governments of the civilized world are engaged in arrange- 

 ments for observation of the Transit of Venus in 1874. As regards the 

 British preparations, the original scheme of observations was confined to 

 eye-observation of the entry and the departure of Venus at the sun's 

 limb, which I regard as the most accurate of all; but, considering 

 especially the risk of weather or accident, it appeared desirable to be pre- 

 pared with a method for utilizing the whole duration of Transit ; and, 

 at the instance of the Board of Visitors of the Greenwich Observatory, 

 the Treasury have sanctioned the fitting up of a photoheliograph of the 

 best class at each of the five British stations. "We are indebted to Mr. 

 De La Rue for the superintendence of the construction and verification 

 of these instruments. Several foreign astronomers have turned their 

 attention to the employment of the helioineter for the same purpose. 



In Chemistry, there has been much work on details, but scarcely leading 

 to any great principle. The theories which have mainly guided the 

 observations appear to be those of isomerism, chemical structure, thermo- 

 chemical research, and physiological chemistry. 



The attention given to Botany has been in some measure differently 

 apportioned to different states. In those which contain within their 

 own limits no very great variety of terrestrial or climatic circum- 

 stances, accurate examination and classification have been studied; 

 but in the more extended countries, and most of all in our own territory, 

 with its enormous colonial extension, the questions of plant-distribution 

 and general biology have been examined, and attention to the structure 

 of fossil plants has increased. The theory of fertilization of plants by 

 insects has gained some assent, and the necessity of observing entomology 

 in connexion with plant-distribution is partially recognized. 



