54 8 THE POPULAR SCIENCE MONTHLY. 



science for his labors, Prof. Adams subscribed bis name, writing 

 beneath it the motto, " Hommage au compatriote de Leverrier." 



The small number and volume of Prof. Adams's publications, 

 after his calculations for the planet Neptune, have been remarked 

 upon. He was, however, an industrious worker, calculating in 

 every quarter of the mathematical field and in mathematical as- 

 tronomy, and is said to have left a large mass of manuscript 

 work, much of which is expected to prove valuable. The Adams 

 prize, of about four hundred dollars a year, to be awarded every 

 two years to the author of the best essay on some subject of pure 

 mathematics, astronomy, or other branch of natural philosophy, 

 was instituted by members of St. John's College soon after the 

 discovery of Neptune, as a testimonial to the honor conferred on 

 the college and the university by the investigation. In 1848 Mr. 

 Adams began the determination of the constants in Gauss's theory 

 of terrestrial magnetism. He resumed the work and was occupied 

 with it in the later years of his life, but had not completed it at 

 the time of his death. In 1852, having been elected in the previous 

 year President of the Royal Astronomical Society for two years, 

 he communicated to the society new tables of the moon's parallax, 

 to be substituted for those of Burckhart. These tables were 

 printed in the appendix to the Nautical Almanac for 1856. 



His memoir explaining the secular variation of the moon's 

 mean motion was communicated to the Royal Society in 1853. 

 The problem baffled solution. The French Academy had at dif- 

 ferent times given prizes for explanations to Euler and Lagrange, 

 but neither of these mathematicians had been able to discover 

 any secular term ; and Euler, considering it established that such 

 a term could not be produced by the principles of gravitation, had 

 recourse to the supposition of a resisting medium. Laplace an- 

 nounced in 1787, as the true cause of the phenomenon, the gradual 

 diminution in the mean action of the sun produced by the secular 

 variation of the eccentricity of the earth's orbit. Theories were 

 also proposed by Damoiseau and Plana, agreeing in principle 

 with Laplace's, but differing slightly in the numerical values as- 

 signed to the acceleration. Adams found that Laplace's explana- 

 tion of the phenomena was essentially incomplete, and suggested 

 corrections to all the theories. Some controversy ensued, at the 

 end of which Prof. Adams was sustained. A calculation of the 

 same problem, made by Prof. Airy in 1880, was also corrected by 

 Prof. Adams. 



Mr. Adams was appointed, in the fall of 1858, Professor of 

 Mathematics in the University of St. Andrews, where he con- 

 tinued his lectures till the end of the session, in May, 1859 ; and 

 late in 1858 he was made Lowndean Professor of Astronomy and 

 Geometry at Cambridge. He held the last position till his death. 



