8 DICTIONARY OF ALTITUDES IN UNITED STATES. 



MISSISSIPPI RIVER COMMISSION (MISS. RIVER COM.). 



These elevations were determined by lines of precise leveling, which 

 extend up the river from near its mouth to St. Paul, across to Lake 

 Superior at Duluth, and to Lake Michigan at Chicago. 



MISSOURI RIVER COMMISSION (MO. RIVER COM.). 



These elevations were determined by a line of precise leveling 

 which extends up the river from its mouth to the three forks in 

 Montana. 



MULLAN, CAPT. JOHN. 



Explorations for a Wagon Road from Walla Walla to Fort Benton, 

 1862. All heights were determined barometrically. 



NEW JERSEY GEOLOGICAL SURVEY (N. J. G. S.). 



Elevations given under this head were determined by lines of accu- 

 rate leveling carried on in connection with the preparation of the map 

 of the State. 



NEW YORK STATE SURVEY. 



These altitudes, consisting mainly of the heights of triangulation 

 stations, were determined by refined trigonometric work. 



NORTHERN TRANSCONTINENTAL SURVEY (N. TRANS. SURVEY). 



These altitudes, chiefly from barometric work, were executed by 

 the Northern Pacific Railway Company. 



PACIFIC RAILROAD REPORTS (p. R. R. REPORTS). 



Under this authority is included work done by the War Depart- 

 ment between 1850 and 1855, for the purpose of finding a practicable 

 railroad route from the Missouri River to the Pacific. 



All the wo/k is barometric and, taken as a whole, is poor, owing 

 mainly to the fact that practically there were no barometric base 

 stations. The hypsometric work of the expedition near the northern 

 boundary, under Governor Stevens, was particularly bad. These 

 remarks concerning the quality of the work apply as well to all the 

 earlier expeditions to the West, owing doubtless to the same cause. 



PARRY, PROF. C. C. 



These elevations were determined barometrically. 



POWELL, MAJ. J. W. 



To this authority is credited the hypsometric work of the United 

 States Geological Survey of the Rocky Mountain Region. The 

 determinations were, made by the use of the barometer or by vertical 

 angles depending upon bases determined by the barometer. 



