traced upon the Surface of the Sphere. 



.'38.5 



TABLE I. 



PARTS OF THE FIGURE REFERRED TO GEOGRAPHICAL CO-ORDINATES. 



To adapt these quantities to the case of polar or astronomical co-ordinates, 

 referred to pole P, and prime meridian PE, we have only to change </>, into 



^ ( j) i and cancel the subscribed accent from 6,- This interchanges sin 



and cos <p ; and also d(f) and d(f), or all the signs in the above Table be- 

 come +. 



