102 THE BEGINNINGS OF AMERICAN ASTRONOMY. 



besides furDisliiug a large number of i^rofessors and teachers of science 

 to the colleges of the country. The observatory of the academy was 

 founded by Bartlett in 1841, and much work was done there, only a 

 small part of which is published. The Coast Survey was a school of 

 practice for army officers, and their ex])erieiice was utilized in numer- 

 ous boundary surveys duriug the period 1830-18no. Col. J. D. Graham, 

 for examx)le, was astronomer of the survey of the boundary between 

 Texas and the United States in 1839-40; commissioner of the ISTortheast 

 boundary survey, 1840-1843; astronomer of the IS'orthwest boundary 

 survey, 1843-1847 ; of the boundary between the United States and 

 Canada, 1848-1850; of the survey of the boundary between Pennsyl- 

 vania and Virginia, 1849-50; of the boundary survey between Mexico 

 and the United States, 1850-51. The names of Bonneville, Talcott, 

 Cram, Emory, and other army officers are familiar in this connection, 

 and their work was generally of a high order. It was in such service 

 that Talcott invented or reinvented the zenith telescope, now univer- 

 sally employed for all delicate determinations of latitude. The me- 

 chanical tact of Americans has served astronomj^ well. The sextant 

 was invented by Thomas Godfray, of Philadelphia, in 1730, a year 

 before Hadley brought forward his proiwsal for such an instrument.^ 

 The chronograph of the Bonds, the zenith telescope of Talcott, and 

 the break-circuit chronometer of Wiulock are universally used to-day. 

 The diffraction gratings of Eutherfurd were the best to be had in the 

 world till they were replaced by those of Eowland. The use of a tele- 

 scope as a collimator was first proposed by Eittenhouse. The pioneer 

 opticians of the United States were Holcomb (1826), Fitz (1846 or 

 earlier), Clark (1845), Spencer (1851). Only the Clarks have a world- 

 wide reputation. Wiirdemann, instrument maker to the United States 

 Coast Survey (1834), had a decided influence on observers and instru- 

 ment makers throughout the United States, as he introduced extreme 

 German methods and models among us, where extreme English methods 

 had i)reviously prevailed. The system of rectangular land surveys, 

 which proved to be so convenient for the public lands east of the Eocky 

 IMountains, was devised and executed by Mansfield, a graduate of the 

 Military Academy. 



The list of army officers who became distinguished in civil life as 

 professors in the colleges of the country is a very long one. Courtenay 

 (class of 1821 at West Point) was professor of mathematics at the 

 University of Pennsylvania, 1834-1836; at the University of Yirginia, 

 1842-43, and was the author of admirable text books. Norton (class 

 of 1831) became professor at New Haven, and wrote a very useful text- 

 book of astronomy in 1839; and the list could be much extended. The 

 excellent training in matliematics at West Point (chiefly in French 



' In 1700 Sir Isaac Newton sent drawings and descriptions of a reflecting sextant 

 to Hadley for his advice. At Hadley's death these were found among his papers. 

 Hadley's device (1731) was undoubtedly derived from Newton's MSS. The Royal 

 Society of London granted £200 to Godfray for his invention, which his brother, 

 Captain Godfray, had previously put into practical use in the West Indies. 



