F. GEOGRAPHY. 2G9 



servations, hourly meteorological observations at the most 

 southerly stations. 



The Western Union and Atlantic and Pacific Telegraph 

 Companies allowed, through the kindness of their presi- 

 dents and managers, the gratuitous use of their wires from 

 these points to the observatory, which has again greatly fa- 

 cilitated the operations of the year. It is proposed during a 

 subsequent season to supply from the observatory at Ogden 

 the time at mean noon each day to the main points upon the 

 Union Pacific and Central Pacific Railroads and the Utah 

 Central Railroad, considerable differences of time having 

 been found to exist between the present determinations at 

 the easterly and westerly extremities of these lines to their 

 different stations along this immense latitudinal stretch. 



At each of the astronomical stations substantial brick or 

 stone monuments have been placed, and meridian marks de- 

 fined with exactness. The true meridian of the place is 

 laid upon the ground, as well as the measurement of a base 

 at each of the points, and its connection with developed bases 

 and vertices of triangles, either established for immediate use, 

 or that they may be taken up hereafter in the prosecution of 

 surveys from these points, either governmental, or those made 

 by corporations or private parties. The main or supply par- 

 ty, under Lieutenants Wheeler and Whipple, operated for 

 the greater part of the season in the western and south- 

 western extremity of the San Luis Valley, the basins of the 

 San Antonio and Cornejos creeks, the head-waters of the San 

 Juan River, and in the valley of the same. The party was 

 composed, besides the commissioned officers, of two topogra- 

 phers, one meteorologist, two odometer recorders, with the 

 usual number of packers, etc. A branch of this party re- 

 turned early in October to close examinations of the ranges 

 fronting the plains between Mosco Pass, or what upon old 

 maps is termed Robideau's Pass, southward to the Trenchera 

 Peak and the crests of the Spanish Peaks, with a view to 

 fill out more definitely the nearly meridional profiles that are 

 to grow out of the survey. Lieutenant Whipple, with the 

 remainder of the party, intended to reach the mouth of the 

 San Juan. Nothing definite as to their results has as yet been 

 reported. 



Lieutenant Marshall's course was alone; the head-waters of 



