358 THE ADDRESSES, LECTURES, ETC., OF 



in which case their appearance should be permanent. Professor 

 Langley, of Pittsburg, has shown by means of his bolometer, that 

 the solar actinic rays are absorbed chiefly in the solar instead of 

 in the terrestrial atmosphere, and Captain Abney has found, by 

 his new photometric method, that absorption, due to hydro- 

 carbons, takes place somewhere between the solar and terrestrial 

 atmosphere ; in order to test this interesting result still further, 

 he has lately taken his apparatus to the top of the Eiffel with a 

 view of diminishing the amount of terrestrial atmospheric air 

 between it and the sun, and intends to bring a paper on this 

 subject before Section A. Stellar space filled with such matter as 

 hydro-carbon and aqueous vapour would establish a material con- 

 tinuity between the sun and his planets, and between the innumer- 

 able solar systems of which the universe is composed. If chemical 

 action and reaction can further be admitted, we may be able to 

 trace certain conditions of thermal dependence and maintenance, 

 in which we may recognise principles of high perfection, applicable 

 also to comparatively humble purposes of human life. 



We shall thus find that in the great workshop of nature there 

 are no lines of demarcation to be drawn between the most exalted 

 speculation and commonplace practice, and that all knowledge 

 must lead up to one great result, that of an intelligent recognition 

 of the Creator through His works. So then, we members of the 

 British Association and fellow- workers in every branch of science 

 may exhort one another in the words of the American bard who 

 has so lately departed from amongst us : 



" Let us then be up and doing, 

 With a heart for any fate ; 

 Still achieving, still pursuing, 

 Learn to labour and to wait.'' 



