74 U. S. COAST AND GEODETIC SURVEY. 



Accordingly let 



dp^_ du 



dp du ' 

 dip d(p 



or 



dp du_l dp p du 

 dip dip u dip u^ dip 



\ ujdip ^\dip u^ dip) 



, d\ 

 dp 



(-9 



1 



u — 



u 



by integration 



l/-»op n — \r\cf I fii ^ I _I_ \r\c, 



,6 2 



loge p = iOg^\U-^+ loge ^ 



in which the constant of integration is taken in the fonn 

 loge 9 • It determines the scale of the projection. Passing 

 to exponentials, we obtain 



