Putnam — Results of Pendulum Observations. 191 



far determined in the United States (exclusive of Alaska) and 

 for the two methods of reduction to sea level already men- 

 tioned. ( — indicates gravity smaller than normal, + greater 

 than normal.) 



Summary of gravity residuals for Coast 



Stations. 











Residuals, observed 





Station. 



Latitude 



minus computed g. 



Coast. 



Bouguer's 



Faye's* 







north. 



reduction. 



reduction. 









dynes 



dynes 



North Atlantic _ 



Calais, Maine 



45 11 



— •021 



— '015 





Cambridge, Mass. 



42 23 



— •009 



— •003 





Boston, Mass 



42 22 



— •007 



— •001 





Hoboken, N. J. 



40 44 



+ •008 



+ •019 





Princeton, N. J... 



40 21 



— •038 



— •032 





Philadelphia, Pa. _ 



39 57 



+ '004 



+ •011 





Baltimore, Md 



39 18 



— •034 



— •023 





Washington, D. C. 



38 53 



+ •014 



+ •026 



Gulf of Mexico . 



New Orleans, La. _ 



29 57 



-•033 



-•033 





Galveston, Texas. 



29 18 



— •035 



— •035 



North Pacific . _ . 



Seattle, Wash 



47 36 



— •135 



— •090 





San Francisco, Cal. 



37 47 



— •016 



— •049 



The variations in these residuals, while not considerable 

 except in a single case (Seattle), are nevertheless of much inter- 

 est. It will be noted that with either method of reduction the 

 largest excess of gravity appears at Washington.! 



A computation of the amount of flattening of the earth has 

 been made from the 33 results for gravity obtained in the 

 United States in 1894 and 1895. These observations are of 

 course not well suited for this purpose except in combination 

 with results in other parts of the world, as the work of 1894 

 was intended to develop the effect of elevation and continental 

 position, and not the variation of gravity with latitude, and for 

 this reason those stations differed little in latitude, and even 

 with the few southern and northern stations added during the 

 past season the extreme range in latitude is less than 18° (from 

 27° 30' to 45° 11'). Nevertheless it is of interest to see how 



* Some slight differences in the last column of this table from values previously 

 given, are due to revised estimates of average elevation. The results from 

 Hoboken, Baltimore, Seattle and San Francisco are from earlier determinations. 



f Commandant Defforges. comparing results obtained on the shores of various 

 oceans came to the conclusion that each ocean possesses a characteristic anomaly 

 in the force of gravity along its shores. " Memorial du Depot General de la 

 Guerre, Observations du Pendule," vol. xv, p. 194. 



