392 JAMES CLERK MAXWELL. 



of being the first of the foreign societies to recognize his merit, by 

 electing him, in 1874, a Foreign Honorary Member. He was elected 

 a member of the American Philosophical Society of Philadelphia 

 in October, 1875 ; Correspondent in the Mathematical Class to the 

 Imperial Academy of Sciences, Gottingen, in December, 1875 ; Hon- 

 orary Member of the New York Academy of Science, in December, 

 1876; Associate of the Amsterdam Royal Academy of Sciences, in 

 April, 1877 ; and Corresponding Member of the Imperial Academy 

 of Sciences, Vienna, in August, 1877. He was Fellow of the Royal 

 Societies of London and Edinburgh, and of the Cambridge Philo- 

 sophical Society. 



His principal contributions to science are the following : — Paper 

 on the "Motions of Saturnian Rings" in 1857 ; "On the Theory of 

 Compound Colours, and the Relations of the Colours of the Spec- 

 trum," which obtained the Rumford Medal, and was read before the 

 Royal Society, March 22, 1860; "Dynamical Theory of the Electro- 

 magnetic Field, including a Note upon the Electro-magnetic Theory 

 of Light," read before the Royal Society, Dec. 8, 1864; "Viscosity 

 and Internal Friction of Air and other Gases," Royal Society, Feb. 8, 

 1866; "Dynamical Theory of Gases," May, 1866; "On a Method 

 of making a direct Comparison of Electro-static with Electro-magnetic 

 Force, with a Note on the Electro-magnetic Theory of Light," in 

 June, 1868. 



His little treatise on " The Theory of Heat" is the most unex- 

 ceptional text-book on physics in the English language. After 

 repeated perusals the reader will still find in it new food for thought. 

 Not only are the abstrusest conceptions put in the simplest language, 

 but also theoretical deductions are illustrated by reference to facts 

 of daily experience. In one place, while speaking of superficial ten- 

 sion, he describes how a heated flat-iron can be used to most advan- 

 tage in causing a piece of paper to remove a grease-spot. The 

 student will find his various essays in the Encyclopaedia Britan- 

 nica the best popular sources of information upon " The Atom," 

 " Attraction," " Capillary Action," " Constitution of Bodies," " Dia- 

 grams," " Diffusion," " Ether," " Faraday," and " Harmonic Analy- 

 sis." We have enumerated above only a few of his more important 

 papers. He was a frequent contributor to " Nature," among the 

 pages of which will be found many reviews by him ; and it is un- 

 derstood that he left many valuable unpublished papers. The most 

 enduring work left by Maxwell is undoubtedly his treatise on Elec- 

 tricity and Magnetism. Since the appearance of this work a new 



