SEARS COOK WALKER. 



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the academies of Andover, Tyngsborough, and Billerica ; then 

 went to Harvard, where he was graduated in the class of 1825. 

 Immediately after his graduation he took up teaching as an oc- 

 cupation and followed it for ten years the first two years in 

 the vicinity of Boston and the rest of the time in Philadelphia. 

 From 1836 to 1845 ^ e was actuary of the Pennsylvania Com- 

 pany for the Insurance of Lives and Granting Annuities. His 

 life in Philadelphia was a period of prosperity and comfort ; 

 he, moreover, early took on a corpulent habit of body, so that 

 whatever influence his circumstances exerted was adverse to 

 any strenuous intellectual exertions, and to the obtaining of 

 adequate physical exercise. Yet his mind was one that could 

 not be idle. " While engaged with his school," says Benjamin 

 A. Gould, in his memorial address,* " he studied medicine, and 

 went through the whole course requisite for the attainment of 

 a degree. He devoted his leisure for a period to the study of 

 natural history, and was no mean proficient in geology and 

 mineralogy, as well as in physics and chemistry. He was an 

 active member of the Pennsylvania Geological Society, of the 

 Committee of the Franklin Institute on Science and Art, and 

 one of the most useful members of the American Philosophical 

 Society. By frequent articles upon scientific topics in the 

 various prints, by elaborate reports upon various subjects to 

 the Franklin Institute, and by monthly announcements in its 

 Journal of occultations and other celestial phenomena, he kept 

 awake the interest and sympathy of the community for studies 

 of this character. Among other labours, he prepared, in 1834, 

 an ingenious set of parallactic tables, by which the time re- 

 quired for computing the phases of an occultation was reduced 

 to less than half an hour. These were calculated for the lati- 

 tude of Philadelphia, and it was his intention to publish them 

 in a more general form adapted to different latitudes. But, as 

 this would have been a work requiring considerable time, he 

 subsequently abandoned the project, believing that he could 

 employ his leisure hours more usefully. He continued the 

 computation of the occultations without interruption for six 



* An address in Commemoration of Sears Cook Walker, delivered before 

 the American Association for the Advancement of Science, at its meeting in 

 Washington, April 29, 1854. From this address many facts concerning 

 Walker's life and work in addition to the above quotation have been drawn. 



