PHYSICAL SCIENCES 49 



Huggins himself, in his presidential address in 1891, 

 recalled that in 1866 he ' had the honour of bringing 

 before this Association, at one of the evening lectures, 

 an account of the first-fruits of the novel and un- 

 expected advances in our knowledge of the celestial 

 bodies which followed rapidly upon Kirchhoff 'a original 

 work on the solar spectrum and the interpretation 

 of its lines. Since that time/ he continued, ' a great 

 harvest has been gathered in the same field by many 

 reapers. Spectroscopic astronomy has become a 

 distinct acknowledged branch of the science, possess- 

 ing a large literature of its own and observatories 

 specially devoted to it. The more recent discovery 

 of the gelatine dry plate has given a further great 

 impetus to this modern side of astronomy, and has 

 opened a pathway into the unknown of which even 

 an enthusiast thirty years ago would scarcely have 

 dared to dream/ 



In the realm of optics generally, many of the most 

 eminent supporters of the Association were pro- 

 minent from the first Brewster, Herschel, and in 

 particular Wheatstone, who described at our meeting 

 in 1835 the spectra of electric sparks passing between 

 the poles of different metals, Stokes (1819-1903), 

 and others, whose work led on to fractions of that 

 executed by three of the greatest figures of the later 

 Victorian and subsequent periods Crookes, Kelvin, 

 and Rayleigh. The extraordinary versatility of the 

 labours of these three men in science, both pure and 

 applied, are beyond any full discussion here ; their 

 names will recur incidentally, but their constant 

 support of the Association (and Kelvin's perhaps 

 above all) demands our most grateful recollection. 



At the earlier meetings of the Association, Dalton 



