CALIFORNIA LINE. 



1C5 



A -word on the subject of the transfer to the ''junction " of the hititude aiul lopgifmlo of the 

 observatory near that point ; the distance between them was so small that the transfer may he 

 considered as having been accomplished by direct measurement. 



Lieutenant Whipple's report to me, November 30, 1849, gives — 



o I n 



The longitude of ohservatory, T 38™ 12^53 ; in arc 114 33 07.95 



The longitude of junction 



Difference 



114 32 51. CI 



16.34 



o / n 



Latitude of observatory, (see report of November 24) 32 43 43.00 



Latitude of junction 



32 13 32.3 



Difference 



11. 6G 



These, corresponding with my computations founded on the same data, were adopted ; hut It 

 must be observed, to prevent future misunderstanding, that it was impracticable to moaMire the 

 azimuth from the iunction of the two rivers, (then under water,) and a point, B, (sec sketch,) 



was 



T3 



ced 



from it. The geographical position of this monument is, consequently. 



In north latitude 

 Uncorrected longitude 



o / // 



32 43 31.6 

 114 33 04.3 



The computation of the azimuth and length of i\ye line of boundary extending from the 

 initial point on the Pacific coast, near San Diego, to the junction of the Gila and Colorado, was 

 based on the following assumption : 



o / // 



Latitude of initial point on the 



Pacific 32 3159.63 



Latitude of junction of Gila and Colorado 



Difference of longitude 



32 43 32.2 

 2 32 24.9 



We compute the azimuth and distance by the formulae given by Puissant, Tmitc de Geodesie, 

 Ed. Ill, Vol. 2, p. 316, using the following notation : ^ ^ a« _ i' 



a 



h 



eaiiatorial radius « = ellipticity 



7 J- Loo- e= 7.8273187 



polar radms ^^o- *" 



b 



a 



Z' = azimuth at the Gila, reckoned from the S. round by W. 

 Z" = azimuth at the initial point " = distance m arc. 



tan. V = I tan. V *-• '" = 1 1*"' ^" 



In the .rheriea" triangle formed by V, I", and P, ^e now compute the angles 180° - Z' and 

 Z" - 180O, the arc <r, and also I, = the latitude of the foot of the perpendicular from the pole, 



and obtain for a first approximation : 



Z" — 180° = 84° ir 25".21 <- - ^^ ^^ ^ '^^ 



