GAEDNEE.] 



GEOGEAPHY ELEVATION OF DATUM-POINTS. 



653 



the elevation of Denver, as here determined, will be made the base for 

 our hypsometric surveys in the Eocky Mountains. 



ELEVATION" OF CHEYENNE. 





Eeet. 



Various datum-planes". 



Elevation in feet 

 above mean sur- 

 face of Atlantic 

 Ocean. 



Cheyenne, U. P. passenger-depot track, by D. P. E. E . 



878. 70 



Above Denver 









5 19G 58 



Cheyenne, IT. P. passenger-depot track 







6, 075. 28 









ELEVATION OF GOLDEN DIRECTRIX. 



Golden directrix, by C. C. E. Pv. - . . 



South T at junction, by D. P. E. E 



Golden directrix 



Do 



12.5 



532.4 



Above south T Junction 

 near Denver. 



Above Denver depot 



do 



5, 728. 98 



ELEVATION OF OGDEN, UTAH. 



Cheyenne 



Ogden depot, by U. P. E. E 

 Ogden 



Second determination. 



Ogden depot, by C. P. E. E. 

 Ogden 



Final result. 



(1) First determination 



(10) Second determination 

 Mean -with weights 



Adopted result. 



Ogden depot track 



1, 749. 00 



4, 326. 28 

 4, 1501. 00 

 4, 303. 3 



BeloTV Cheyenne . 



Above Pacific Oce.in. 



By IT. P. E. E 

 ByC.P.E.E. 



6, 07,5. 28 



4, 326. 28 



4, 301. 00 



4, 303. 3 



The result by the Central Pacific of California is given much the 

 greater weight, because it is a continuous line of levels run by one rail- 

 road-company, the same chief engineer, Mr. S. S. Montague, superintend- 

 ing the running of all the lines and the making-up of preliminary and 

 final profiles. The length, also, of this line is only about one-third of that 

 from the Atlantic Ocean. 



If we consider these lines as one long chain of levels from the Atlantic 

 to the Pacific, we have connected railroad-levels extending not less than 

 thirty-five hundred miles, and reaching the Pacific Ocean with an error 

 of 25 feet. If we form a continuous line of levels by joining those of the 

 Pa., P. F. W. & C, C. E. I. & P., U. P., and C. P. E. E.s, they reach the 

 Pacific with an error of -|-13 feet. 



If a chain is formed by putting together the lines from New Orleans 

 to Cairo ; thence by I. M. E. E. to Saint Louis ; thence by Mo. P., K. P., 

 D. P., U. P., and C. P. E. E.s, the line is thirty-two hundred miles long, 

 and reaches the Pacific Ocean with an error of -f 2G feet. In this chain, 

 the levels of eleven different railroads are connected 



