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Show 8 Ex. Doc. No. 41. · W 1 · 1 to called the instruments and other convenic.nGes In a. Hng o_n 1.l.' 'l'hi~ was quite sufficient for all the object~ for ~urh an e\'pe< J Ion. . • . . rr. . f th app.e. rtam· m· g <1·1 r eclly to our military . wants, but tnSUt1tl Cient ·t or I e o• rganJ· zatt·o n an< 1 ou tr1.1 t of a• 1n• rty m lende<l for e·x p ol ra 10b1 1. , . n submirtincr the following notrs, they shoulcl be ~e c ctv c a~ o CI va~ tt·o ns rna< lbe at 1'ntervals snatched fro. m otherb dulle1s , and w·t t1h ' ant' e:x pe< 1.t ll· on ,,, h osc 1n ove1n en t were d Itedec.l y ot1 er con Si·t ra tonsf than those which would influcn ·e the news ancl convemcn · s o an ex p 1 ore r. · k t We left Washington on the Gth of June, u.nable to procure a P.oc e ·~hronomctcr, or telescope of power sufTic1e~t to o~scrve ecl~pscs; b t through your intcrC'ession, and by the ktn~lncss of the Clllef of Iluy <1 r ograp 11 y , {J · S · N ·' we were JHOYiciC'd w1.t h two cx<'<1'' llcnl th box hronometcrs No. 783 and No. 2,075, by Park 1n !SOn and ' roc . am, ~nd we receiv'cd frotn the bureau two of G~mbcy'~ 8~- inch sextants. Crossing the All~ghanies the stage capstzed w1th us~ and placed the chronometers in great danger,. uut the prudence of Nl.r. 13cstor, who .carried them in a ba ket on hr arm, saved them fro~ destruction. Their rates were changed very mate.ri~lly by the arc1.dcnt, but subsequent observations show<'d no other InJtuy had been ,tncurr~d. Elaborate observations for lime and rate were made at St. Lo UlS; from which place, being tolcra bl y well e~tab 1 ishc<l in geographical position, it was intended to carry the longttude by chronome.ter? but, on reaching Fort Leavenworth, th_c hrono.metcrs were aga.ul found to haTe changerl their rates matenally, ow1ng to t~e peculiarly unsteady ancl jarring motion of the steamer upon wh.rch we asccnde<~. The meridian of Fort Leavenworth, as determmed by Mr. NIcollet, is therefore taken as that to whi h all the determinations of longitude as far a~ Bent,s fort, by the chr~nomet r, are re~erred, and any chancre wh1ch suo. cqucnt observatiOns may make m the longitude of Fort Leavenworth, will be common to them. The travelling rates of chronometer 783 w re, as the ob ·crvations will show, very uniform, and longitudes deduced from it, compared with direct measurements of lunar distances macle 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, thenee ·ro~sing the mountains to the Gila river, some irrcgulttrily in the rates is discoverable, until we reach camp 83, October 26th, on the Gila river. From that point (camp 83) to San Diq?;o, on th Pacific, the rates were very uniform. Assuming Capt ainU c I cher's cl etermination of that point, 7h. 48m. 4.4s., west from Greenwich, an!l carrying my longitudes back, they compare ·well with the longitudes dcriYcd irom the direct measurements of lunar distances made at different poiuts on the route. The longitude bet ween the camps of October 9th an<l Octo bcr 26th, are deriYed from direct measurements, and from lunar di tan<.:es. OJ the latitudes. The latitudes were determined by measuring with one of the Gambey sextants the double altitudes of stars ncar the meridian, and at all important points by observations on north and south stars as nearly as they could be obtained of equal altitudes. At these Ex. Doc. No. 41. 9 last points, where the observations arc multiplied, then places may be depended upon t0 the neare t five second . • • Of lo cal time. The local t~mc was., .in all ca e~, determinecl by al titudes of the heavenly bodtcs on ddlerent . id es of t he meridian. . The a tronomical ob ervations, in number were computed 1n the first place, by my elf and Mr. H ' to r, an/. ub equently b;· Professor J. C. Hubb~rd. ~'here uJt, a. gi\·en in the appendix, arc thc.final computat10nsofl)rofe sor H ubbard, whose well- arned r;putat10n as ~ computet~ ctJtitleJ his work to entire confid nee. 'Ihcse ?bservatrons c tab It -h the grographical position of 52 points ~xt nc!tng from Fort Lca,·enworth to the Pacifi <.:, most c![ which li~ ln regiOns before undctermin d. IIcigl&ts above t!te sea. At Fort Leavenworth, through the liu crality of the medi ·al clcpartment, I wa furni hccJ. with a syphon barometer by Bunten No. 515, the comparison of which, with the standar:i at Paris i~ given in the subjoined note. ' Observatoire.-Comparaison dn barom \ trc <t yphon, No. 515 de Tiunten, a'l)ec le barom,(:t1·e de l'observatoire. Paris, le. . . . . • . . . . . . . . . . . . . . • . . . . . . . . . . . . . . . . . . . . . • . . • • 1843 Le bar.omctr~ ~o. _515, donne des hauteurs plus grand s que celles qut sont rndtquees par 1 baromctrc de l'ob ·crYatoirc la dif-ference est de 0.45 centicmcs <.le millim ctr . ' J3aromctre, 12.9 12.0 11.3 10.3 8.7 5 No. 515 . : ............................. . ~ Ob ervatotrc ...•..•.•...........•.•... , 759.1!.) 758.74 D i (f6 r en c e . • • • • • • • • • . . . . • • . • . • . . • • , • +O . 45 -- L 'ouservatoiro. No. 515. 758.20 +0.40 758.60 12. 5 761.50 +0.50 762.00 11.8 762.14 +0. 56 762.70 11.0 75 .OG +0.44 75 .50 10.0 753.80 +0.35 756.15 8.8 2.25 +0.45 - P AltiS, le 3 Pcvri er, 1843. GORYOZ. The di cus ion of the data up on whi ch the heig hts indicated by the bar om c t e r haY e be c n f o u n d d, w o ul d , if pur s tH' d, occupy some space; for the present, it will be sufTi cient to say that the basis of |