Figure 17. Repsold-Bessei reversibli pendulum appa- 

 ratus as made in [875, and used in the gravity work of 

 the I s < oasi and Geodetic Survey. Continental 

 desists continued to favor the general use of convertible 

 pendulums and absolute determinations ol gravity, while 

 their English colleagues had turned to invariable pi min- 

 iums and relative determinations, except ibi base stations. 

 Perhaps the Rrsl important American contribution to 

 gravity work was ( !, s. Peirce's demonstration of the 

 error inherent in the Repsold apparatus through flexure 

 of die stand. 



Peirce. I'pon receiving notice of his appointment, 

 the latter promptly ordered from the Repsolds a 

 pendulum similar to the Prussian instrument. Since 



the linn of mechanicians was engaged in making 

 instruments for observations of the transit of Venus in 



tire [8. ( harles Sander Pi sta 1839-1914), 

 son of Benjamin Peine. Perkins Professor of 



Vstronomj and M it Harvard College. 



C. S. Peirce graduated from Harvard in 1859. 

 From 1873 to i8gi, as an assistant at the 1 .S. 

 ( oast and Geodetic Survey, he accomplished the 

 important gravimetric work described in this arti- 

 cle. Peirce was also interested in many other fields, 

 but above all in the logic, philosophy, and history 

 of science, in which he wrote extensively. His 

 greatest fame is in philosophy, where he is regarded 

 as the founder of pragmatism. 



1874, the pendulum foi the < oast Sun ey could not be 

 constructed immediately. Meanwhile, during the 

 years 1873-1874, Charles Peirce conducted a party 

 which made observations ol gravity in the Hoos.ie 

 Tunnel near North Adams, and at Northampton and 

 Cambridge, Massachusetts. The pendulums used 

 were nonreversible, invariable pendulums with 1 1 

 bobs. Among them was a silver pendulum, but 

 similar pendulums of brass were used also. 56 



56 The pendulums with conical bobs are described and illus- 

 trated in E. D. Preston, "Determinations of Gravity and the 

 Magnetic Elements in Connection with the United States 

 Scientific Expedition to the West Coast of Africa, 1889-90," 

 Report of the Superintendent 0/ the Coast and Geodetic Surt ey j 

 bington, 1891 ,1, app. no. 12 



PAPER 44: DEVELOPMENT OF GRAVITY PENDII IMS IN THE T 111 (I Nil RY 



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