| Show ii tha i th 1 solar 11 parallax X eb 80 tiia jlia the tho E expedition to chili R report 0 ot 0 t lini mi 0 i t i T 8 yil I 1 U S naval 0 washington thursday SIR sin I 1 have hav e the honor toi tol communicate to douthe results of the observations apeci specially made madd by the united states naval navai astronomical expedition to determine ehfe bolar parallax i the suns suna distance froglia from aid ald the lia arth i J it will be remembered ay the department that dr in eminent geometer of bf germany suggest suggested edthe the practicability of de this fundamental astronomical I 1 datum from observations of venus near the them inferior I 1 conj conjunction diction ric lic tion instead of awaiting the rare tare phean phe of i transita of the plan pian planeta et across cros thel thol suns buns disc chatan that an expedition to the f south Southern ern hemisphere was proposed to the department by myself for the purpose of making these observations ions similar observations to be tie made mad eat at the naval observatory woula test the method and that the elain earnest commendation of the he measure by physicist physicists both and this country induced congress to authorize the expedition by special grants inthe in the appropriation bills approved ah ft 1848 and 1 1849 1 phar phu phie pt ii we merd werd were absent from the united states and a half years and eions constituting the more immediate jobje object ct of the expedition extended through parts of each tach of the me years froal rom november 1849 to septem september ei 1852 inclusive so 0 many cla cia classes ases of observations lons ions were weep embraced in the plan of operations adopted by the department that our small party was almost constantly occupied in observatory daty proper and it was not hot possible to prepare any rany of odthe the data for the final computations until un ift erthe return of the elii o peli pell tion to theA the theu united nOted states then our first efforts enores were to proper form for the coln coin computer all th observations of the tho planets venus and biars mars and the stars with which they hadl hadi f been compared whilst our men of science had bad bation ad beet unanimous in alvo aavo advocating cating the q ration of an jj expedit expedition lop iop because of the additional mass of important information certain to be bp collected by it there were some who en pertained an opinion that the he method of deter the parallax proposed by dr gerling would not afford a result ad as reliable re lable labie as had been derived from io tle tie e transita transits tran sits of venus in 1761 and 1769 for obvious reasons therefore it was vas proper that tha the discussion of the results from our observation should be in trusted to an astro astronomer noler thoroughly com competent potent t to appreciate the problem yet wholly uncommitted as to the comparativo comparative e odthe of the two methods L Unde rhe sanction of the department dr 13 JL aa A jit of cambridge massa mabs mass was selected for the durpos pur pos and the elaborate reh ref refinement with which he has executed this difficult and delicate task is ample evidence that the confidence of the department was not misplaced misplay ed his report does him great honori it will fill tro fro rom in to pages of volume 3 of the results of the expedition the larger portion portio ig of it and ind all the ibe remainder of the volume being already printed ft the result t obtained by bumfor him for the suns equatorial j horizontal parallax is 8 or 0 less ess esa than the value commonly aua and he be concludes that ye e may assume with advantage 85 8 correspond corresponding iD to a distance fro from in that luminary of statute miles As ithe the information loof loaf is of high ligh interest to as tron tronc omers I 1 have the honor to suggest that it be made known own in advance of the publication of the volume I 1 have the te honor lionor to be your tour obedient I 1 J M GILLIS GILLISS s hon non 1 I Secre secretary faey fary of of the navy |
