68 ANNUAL RECORD OF SCIENCE AND INDUSTRY. 



geneity of large tracts of tlie eartli's surface is about the 

 same in every part of the earth itself: 



* The stations at which deflections, A, are not computed were situated in the midst 

 of plains, where the deflection, A, would not amount to 0.4", the uncertainty of the 

 determination of D. 



t Carried to SO miles. 



