Tables 87-88. 

 LENGTH OF THE SECONDS PENDULUM. 



TABLE 87. — Length of Seconds Pendulum at Sea Level for Different Latitudes.* 



107 



• Calculated from force of gravity table by the formula /: 

 centimetres, or 0.000235 inches, or .0000196 feet. 



-Sl'"'^' ^<^'' each 100 feet of elevation subtract 0.000596 



TABLE 88. — Lengtb of the Seconds Pendulum.* 



Range of latitude included by 

 the stations. 



From+67°o5'to— 33°56' 



—51 



—60° 



+74° 53' 

 +38^40' 

 +79° 50' 

 +79° 50' " -51° 

 0° o' " +67° 



+79° 51' "—51" 



+79° 50' 

 +79° 50' 

 +79° 50' "-62' 



-51" 

 —62° 



45' 

 59' 

 35' 

 04' 

 35' 



35' 

 56' 

 56' 



Combining the above results 



Length of pendulum in metres 

 for latitude </>. 



0.99063 1 + , 



0-990743+ 

 0.990880+ 

 0.990977 + 

 0.991026+ 



0-990555+ 

 O.991017+ 

 0.990941 +, 

 0.990970+ 

 O.991011 + 

 0.990918+ 



005637 s 

 ,005466 s 

 ,005340s 

 .005142 s 

 ,005072 s: 

 ,005679 s 

 .0050S7 s 

 ,005142 s 

 .005185 s 

 ,005105 s 

 .005262 s 



n'</> 

 n-<j[> 

 n^ 

 n2<f, 

 n-^ 



n-^ 



n-^ 



c.9909io+.oo529osin'^ 



Correspond- 

 ing length 



of pendulum 

 for lat. 45° 



0.993450 



0.993976 

 0-993550 

 0.993548 

 0.993562 



0-993395 

 0.993560 

 0.993512 



o-993554t 



0-993563 



0-993549 



0-9935 55 



Refer- 

 ence. 



3 

 4 

 5 

 6 



7 

 8 



9 

 10 

 II 



1 Laplace : " Traite de Mecanique Celeste," T. 2, livre 3, chap. 5, sect. 42. 



2 Mathieu : " Sur les exptjriences du pendule;" in " Connaissance des Temps 1816." 

 Additions, pp. 314-341, p. 332. 



3 Blot et Arago: " Recueil d'Observations geodesiques, etc." Paris, 1821, p. 575. 



4 Sabine : " An Account of Experiments to determine the Figure of the Earth, etc., by 

 Sir Edward Sabine." London, 1825, p. 352. 



5 Saigey: "Comparaison des Observations du pendule \ diverses latitudes; faites par 

 MM. Biot, Kater, Sabine, de Freycinet, et Duperry; " in "Bulletin des Sciences Mathe- 

 matiques, etc.," T. i, pp. 31-43, and 171-184. Paris, 1827. 



6 Pontecoulant: "Theorie analytique du Systeme du monde," Paris, 1829, T. 2, p. 466. 



7 Airy : " Figure of the Earth ; " in " Encyc. Met." 2d Div. vol. 3, p. 230. 



8 Poisson: "Traite de Mecanique," T. i, p. 377; "Connaissance des Temps," 1834, 

 pp. 32-33 ; and Puissant : " Traite de geodesic," T. 2, p. 464. 



9 Unferdinger : " Das Pendel als geodatisches Instrument ; " in Grunert's "Archiv," 1869, 

 p. 316. 



10 Fischer : " Die Gestalt der Erde und die Pendelmessungen ; " in " Ast. Nach." 1876, 

 col. 87. 



11 Helmert: "Die mathematischen und physikalischen Theorieen der hoheren Geo- 

 dasie, von Dr. F. R. Helmert," IL Theil. Leipzig, 1884, p. 241. 



12 Harkness. 



• The data here given with regard to the different determinations which have been made of the length of the 

 seconds pendulum are quoted from Harkness (Solar Parallax and its Related Constants, Washington, 1S91). 

 t Calculated from a logarithmic expression given by Unferdinger. 



Smithsonian Tables. 



