214 ANNUAL HECOKD OF SCIENCE AND INDUSTRY. 



gulating party was united for a portion of the time with one 

 of the topographical parties for mutual support. This party 

 took the eastern portion of the field, which is separated from 

 the western at not far from 110 30' W. long., and includes 

 that part of Utali above 38 N. lat. which lies east of the 

 Green and Colorado rivers in all about 10,000 square 

 miles. The party carried the secondary triangulation over 

 this district, with stations averaging ten miles apart ; made 

 a connected plane-table map of the whole, and complement- 

 ed the work with orographic sketches. 



The second topographical party, occupying the western 

 portion, Avas assigned an area more mountainous than that 

 to the east, embracing about 0000 square miles : in this it oc- 

 cupied topographical stations at average distances of about 

 ten miles, and measured all the angles of nearly every trian- 

 gle in the secondary extension; and, like the first party, made 

 sketches and a plane-table map of the entire area. 



Besides this purely topographical work, mercurial barome- 

 ters were carried by each field party ; and observations were 

 made to connect every camp with the base-station at Mount 

 Pleasant, where observations were taken four times a day, 

 and also hourly during eight days in each month. All the 

 geodetic points and topographical stations were also con- 

 nected by barometric observations, either with the camps, 

 the base-station, or both ; and the altitudes of all located 

 points were observed by the measurement of vertical angles. 



This hypsometric work is deemed by the director of the 

 survey to be of the greatest importance in the classification 

 of lands, and in determining the best methods of utilizing 

 the waters of streams for irrigation. On account of its prac- 

 tical utility to the agricultural industries of the country, 

 Major Powell suggests the establishment of a hypsometric 

 base-line from Lake Michigan to the Pacific Ocean, from 

 which lateral lines could be run to the base-stations used for 

 each season. The methods of levelling by which were deter- 

 mined the elevations of points along the Pacific Railway (now 

 used as a general base) were not of sufficient refinement for 

 ] resent needs. The work requires great care and thorough 

 discussion, and should be undertaken by the Interoceanic 

 Geodetic Connection of the Coast Survey. New tables 

 also should be made, based upon series of observations in 



