80 JAMES CLERK MAXWELL 



first additional examiner for the Mathematical Tripos, 

 in accordance with the scheme which he had done so 

 much to promote in 1868. 



Many of his shorter papers were written about the 

 same time. The ninth edition of the Entyclop&dia 

 Sritannica was being published, and Professor Baynes 

 had enlisted his aid in the work. The articles 

 "Atom," " Attraction," "Capillary Action," "Constitu- 

 tion of Bodies/' " Diffusion," " Ether," " Faraday," and 

 others are by him. 



He also wrote a number of papers for Nature. 

 Some of these are reviews of books or accounts of 

 scientific men, such as the notices of Faraday and 

 Helmholtz, which appeared with their portraits ; 

 others again are original contributions to science. 

 Among the latter many have reference to tho 

 molecular constitution of bodies. Two lectures tho 

 first on "Molecules," delivered before tho British 

 Association at Bradford in 1873 ; the second on tho 

 " Dynamical Evidence of tho Molecular Constitution 

 of Bodies," delivered before the Chemical Society in 

 1875 were of special importance. The closing 

 sentences of the first lecture have been often quoted. 

 They run as follow :~ 



" In the heavens we discover by their light, and by their 

 light alone, stars so distant from each other that no material 

 thing can ever have passed from one to another ; and yet this 

 light, which Is to us the sole evidence of the existence of these 

 distant worlds, tells us also that each of them is built up of 

 molecules of the same kinds as those which ue find on earth. 

 A molecule of hydrogen, for example, whether in Sirius or in 

 Arcturus, executes its vibrations in precisely tho same time. 



"Each molecule therefore throughout the universe tears 



