ASTRONOMICAL POSITIONS 



THE RIO BRAVO DEL NORTE. 



D. 



DEL 



Office of Survey of the United SrATES and Mexican Boundary, 



WasUnghn, D. C, May 22, 1856. 

 Sir: In my communication of February 9, 1856, I presented to you tlic final results for the 

 lon^-itudes of tlie astronomical station, established under your direction in the year 1853, near 



the mouth of Rio Bravo del Norte, the same having been computed with corresponding observa- 

 tions made at Greenwich, Philadelphia Higli School, and RadclifFe observatories. 



I have now to present, in a tabular form, the individual results of all the observations made by 

 you and under your orders for the longitudes and latitudes of the primary astronomical positions 

 on and near the Rio Bravo del Norte, established in connexion with the survey of the United 

 States and Mexican boundary. 



I. — Longitudes. 



The positions thus determined are eight in number, being enumerated as follows in the 

 order of place from the west: 

 a. Frontera. 

 a}. San Elceario. 

 h. El Paso del Norte. 



c. Mouth of Caiion. 



d. Presidio del Norte. 



e. Fort Duncan, Texas. 

 /. Ringgold Barracks. 



g. Mouth of Rio Bravo del Norte. 



All the observations made at these places, together with the computations, as well as the 

 elements and data used therein, are Jierewith presented in a tabular form, comprising the corre- 

 sponding observations made at Greenwich, Cambridge, Philadelphia High School, and Radcliffe 



observatories.* 



Attached to this is also a recapitulation of the results, from which are deduced the final longi- 

 tude adopted for each station, the papers being marked a, a\ b, c, d, e,/, g, to each of which 



I will briefly call your attention. 



a. Frontera.~The observations at this place extend through four lunations, commencing 



) 



— ^ — ' — y ' _ — 



tnde—l'' 6" 13'.02 west of Greenwich. 



Th^iiti computations are to be deposited in the Department 



