63 



Feet 



1) From Boston State House and Northampton Church, 3G5177.G0 



2) „ „ and Plymouth Court House, 365653.00 



3) „ „ and Amherst College Chapel, 365025.0(j 



4) „ Springfield Court House and Plymouth Court House, 305888.43 



5) „ „ and Highland Light, Cape Cod, 365984.43 



6) „ Greenfield Church and Gloucester Church, 365420.70 



7) „ Boston State House and Pittsfield Church, 364193.11 



8) „ Plymouth Court House and „ 364790.00 



9) „ Boston State House and Williamstown Church, 304519.42 



Sum of the first 6 results 6) 3149.22 



Mean of the first 6 results 305525.00 



The three last of these results are rejected on account of their dis- 

 crepancy from the mean. The astronomical observations for deter- 

 mining the longitude at Pittsfield and Williamstown are supposed by 

 Mr. Borden to have been affected by mountain attraction ; and he 

 adopts the value of the degree perpendicular to the meridian as de- 

 rived from the inclination of the meridians, in preference to the mean 

 result given by this last table, in consequence of the discrepancies 

 among its single results. 



With the values of the meridional perpendicular degrees thus 

 found, Mr. Borden calculated the equatorial radius, polar semi-axis, 

 and ellipticity of the terrestrial spheroid, and the differences in value 

 of the meridional degrees of 41° 21' 30", 42° 21' 30", and 43° 21' 

 30". His results are as follows : — 



Meridional degree for the latitude of the State House, 364356 feet. 



Perpendicular degree for the same latitude, 365511 feet. 



Equatorial radius, 20914728 feet = 3961.123 miles. 



Polar semi-axis, 20854128 feet = 3949.646 miles. 



Ellipticity, ^ T nearly of the equatorial radius.* 



Length of meridional degrees, the latitude of whose middle point 

 corresponds to 



, /; Feet. Difference. 



41 21 30 = 364300.96 



-f 55.04 feet. 



42 21 30 = 364356.00 



+ 55.22 „ 



43 21 30 = 364411.22 



* Combining the meridional degree measured in Peru in latitude 1° 30' 

 with the meridional degree measured in Massachusetts, they give an ellip- 

 ticity of l-313th nearly of the equatorial radius. 

 H 



