X 



Edwaed James Stone was born in London on the 28th February, 

 1831. As a child his constitution was delicate, so that soon after 

 entering the Citj of London School his health broke down, and he 

 was sent to the country for several years, where he was educated at 

 a private school until ready to enter King's College, London. 



Although his higher education only began at the age of 20, he 

 took a scholarship at Queens' College, Cambridge, in 1856, whence 

 he graduated as Fifth Wrangler in 1859, and was immediately 

 elected to a Fellowship. The following year he was selected for the 

 important position of Chief Assistant at the Royal Observatory, 

 Greenwich, his predecessor in that post, the Rev. R. Main, having 

 been appointed Radcliffe Observer at Oxford. 



With what diligence he applied himself to the duties of his office 

 and how wide a view he took of his responsibilities, is made evident 

 by the series of important papers which he soon afterwards began to 

 communicate to the Royal Astronomical Society. 



His work was obviously congenial, he had a marked inborn 

 capacity for dealing with large masses of figures, a high estimate of 

 the practical importance of the work on which he was engaged, 

 sound mathematical training, and an almost impatient desire to 

 derive from the long series of Greenwich observations results which 

 would be of immediate value to science. 



It is not difficult to trace the origin of the line of research which 

 Stone subsequently followed with such zeal and pertinacity. Fresh 

 from study of the lunar and planetary theories, so far as these 

 subjects were treated in his Cambridge curriculum, the attention of 

 the young astronomer was early arrested by the interesting problems 

 which were then opening up in consequence of the researches of 

 Hansen and Le Yerrier. 



We have a statement of the motif of Stone's first work in the 

 introductory paragraphs of his first astronomical paper,* " Deter- 

 mination of the Solar Parallax from N.P.D. Observations of Mars at 

 Greenwich and Williamstown." 



" In his tables of Mars, published in the 4 Annals of the Imperial Observa- 

 tory, 5 Paris, 1861, M. Le Yerrier remarks that it is impossible to reconcile 

 the observations of Mars with theory without attributing to the perihelion a 

 motion greater than any which can be obtained except by a sensible increase 

 of the received planetary masses ; that the necessary agreement between 

 theory and observation could be obtained by increasing the received value of 

 the mass of the earth in proportion to the sun's mass by not less than a tenth 

 part, but that such an increase in the received value of the earth's mass 

 would necessitate a corresponding increase in the received value of the 

 sun's mean equatorial horizontal parallax of a thirtieth part. 



" M. Le Yerrier deduced the same result from a discussion of the latitudes 



* 'Monthly Notices R.A.S.,' vol. 23, 1863, p. 183. 



