8 w Ex. Doc. No. 41. 





in Washington to collect the instruments and other conveniences 

 for such an expedition. This was quite sufficient for all the objects 

 Tippertaining directly to our military wants, but insufficient for the 

 organization and outfit of a party intended for explo'ralion: In 

 submitting the following notes, they should be received as observa- 

 tions made at intervals snatched from other duties, and with an ex- 

 pedition whose movements were direc'ted by other considerations 

 than those w^hich would influencg the views and " conveniences of 



ah explorer. . ' , 



We left Washington on the 6th of June, unable to procure a pocket 

 chronometer^ or telescope, of power sufficient to observe eclipses; 

 but through your intercession, and by the kindness of the Chief of 

 Hydrography, U. S. N,, we were provided with two excellent box 

 tihronometers. No. 783 and No. 2,075, by Parkinson and Frodshara, 

 and w:e received from the bureau two of Gambey's 8|-inch sextants. 



Crossing the- Alleghanies the stage capsized with us, and placed 

 the chronometers in great danger, but the prudence of Mr. B.estor, 

 who carried them in a basket on his arm, saved them from destriic- 

 tion.' Their rates were changed very m-aterlally by the accident, but 

 subsequent observations "showed no other injury had been incurred. 



Elaborate observations for time and rate were made at St. Louis; 

 from which place", being tolerably well established in geographical 

 position, it was intended to carry the longitude by chronometer, but, 

 on reaching Fort Leavenworth, the chronometers were againfound 

 to hav^e changed their rates materially, owing to the peculiarly un- 

 steady and jarring motion of the steamer upon which we ascended. 



The meridian of Fort Leavenworth, as determined by Mr. Ni- 

 collet, is therefore taken as that to which all the determinations 

 of longitude as far as Bent's fort, by the chronometer, are referred, 

 rtrtd any change which subsequent observations may make in the 

 longitude of Fort Leavenworth, will be common to them. The 

 travelling rates of chronometer 783 were, as the observations will 

 show,, very uniform, and longitudes deduced from it, compared 

 with direct measurements of lunar distances made at various points, 

 give satisfactory comparisons as far as camp 70, October 9th, on 

 the Rio del Norte. At this point we left the wagons, thence crossing 

 the mountains to the Gila river, some irregularity in the rates is dis- 

 coverable, until we reach camp 83, October 26th, on the Gila river. 



From that point (camp 83) to San Biego, on the Pacific, the rates 

 urere Very uniform. Assuming Captain Belcher's determination of that 

 point, 7>^. 48m. 44^., west from Greenwich, and carrying my longi- 

 tudes back, they compare well with the longitudes derived Irom the 

 direct measurements of lunar distances made at different points on 



the route. 



amp 



are derived from direct^measurements, and from lunar distances. 



i - Of the latitudes. 



The latitudes were determined by measuring with .one of the 

 Gambey sextants the double altitudes of stars near the meridian^ » 

 and at all important noints bv observations; on hnrth c\nf^ cnuih cfi 



rs 



m nearly as they could be obtained of equal altitudes. At these 



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