PRINCIPAL DETERMINATION OF LONGITUDE USED. 
List of principal positions used in compiling the map and their adopted longitudes. 
Place. 
Longitude. 
Authority. 
Point Seul-choix, Lake Michigan i yi 
Mouth of — Weiss (pilot-house) 
New Orleans C 
St T T 1 i 
Fourth Principal Meridian, in Wisconsin 
Fourth Principal Meridian, mouth of Illinois river ا‎ 
Fifth Principal Meridian, in Missuri.. 
Sixth Principal Meridian, in latitude 369 30’ 
j—— in latitude of New Orleans ............. 
Month of St. 
Cape Nut, mouth of Sabine river Sameer ene co" ———A— —— 0| 
Mouth of Big Sioux river 
Preston 
Fort Riley 
Pembina 
Fort Arbuckle 
San Antonio 
Fort Belknap 
Bent's New Fort, (Big Timbers, Arkansas river) 
Date Old 77 09۳ موی‎ —M— مه نج نز‎ ——— "immo momo 
Nealawa 
Albuquerque 
Copper Mines 
Camp near mouth of Bear river 
Camp near Great Salt lake 
San Bernardino meridian 
San Pedro 
Fort Walla-Walla 
Dalles of the Columbia 
104 02 07 
ی 
Captain J. N. Macomb, T. E. 
Captain A. Talcott, Eng. 
Nicollet, (see Report.) 
Nicollet. 
Major Long and Mr. Nicollet. 
Major J. D. Graham, T. E. 
Lieutenant I. C. Woodruff, T. E. 
Colonel J. E. Johnston, T. E. 
Captain J. Pope, T, E, 9 
Lieutenant G. K. Warren, T. E. 
—_ C. Frémont, T. E. 
| Major W. H. Emory T. E. 
Mexican Boundary 
Lieutenant A. W. Whipple, T. E. 
Mexican Boundary Commission. 
Captain J. C. Frémont, T. E. 
Captain J. C. Frémont, T. E. 
Coast Survey. 
Commander Wilkes, U. 8. N. 
Lieutenant H. L. Abbot, T. E. 
۶ A more recent determination of Captain Pope makes it 104° 03’ 56". 
109 
