WALKER, SEARS COOK

(1805-1853), an American astronomer, born in Wilmington, Ma . He was educated at Harvard. For several years he taught school in the vicinity of Boston and later in Philadelphia, meanwhile being also engaged in scientific pursuits. In 1845 he received an appointment in the Washington Observatory and two years later, shortly after the discovery of the planet Neptune, he identified that planet with a star observed by Lalande in 1795. He then took charge of the longitude computations of the United States Coast Survey and developed with Profe or Bache the method for determining the differences of longitude by telegraph, which was first pus into succe ful operation in 1849. e died in Cincinnati in 1853.