38 



Tribune Extras Lecture and Letter Series. 



irn Union Telegraph Company. Connections may be at 

 any time mad>3 with the wires ot the Atlantic and Pacific 

 Company, and of the Deseret Telceraph Company of 

 Utah. To Prol. H. B. Herr ot the Lohigh TJuiversity of 

 Pennsylvania the superintendence of the construction of 

 this building and the charge of the observations neces- 

 sary to connect it with the observatory ar Salt Lake and 

 that of the Lake Survey at Detroit were delegated. He 

 was unable to perform the latter work, having to return 

 to duty at the university. The observations were made 

 later in the season by Dr. F. Kampf. Tiiree main field 

 astronomical parties were organized, and took the field 

 about the 1st of June, 1873, leaving it on or about the 15th 

 of November. They were in charge of Assistants J. H. 

 Clark, Dr. F. Kampf, and Win. W. Maryatt, respectively. 

 Prof. T. H. Safford of Dearborn Observatory, Chicago, 

 joined the survey on the 15th of June, and conducted 

 the observations necessary for the determinations of 

 Santa Fc and Fort Union, N. M. The following mam 

 field scations were occupied during the past field 

 M ason : 



(1.) Santa F. S. M. 



12.) Kurt I'liinii, N. M. 



(;!.) Trii:iilm1, Col. 



(1 ) L;il>r:iu, i "I. 



(5.) Colorado Spring, Col. 



(0.) Hughes, Col. 



(7.) Georgetown, Col. 



(S. ) Otden, Utah. 



<y.) Wiiiuemucca, Nev. 

 (10.) Virginia City, Nev. 

 (11.) Golden. Montana. 

 (12.) Greea River, Wyomine. 



STATIONS DETERMINED AND RESULTS ATTAINED. 

 During the years 1871, 1872, and 1873 the results, now 

 m stly calculated, give with the utmost exactness now 

 attainable the latitude and longitude of 21 stations in 

 the interior area west of the 100th meridian. Tiieso 3e- 

 tcrminatious are accurate and trustworthy, as the prob- 

 able errors show a minimum compared with any as yet 

 obtained ot this class of work, either in this country or 

 abroad. They have already been used in checking the 

 surveys made upon the railroads, so that these lines of 

 communication from the Mississippi to the Pacific can 

 he perfectly laid down upon the general map. A scheme 

 developing from the lino of stations reaching from 

 Omaha to San Francisco has been begun, which, 

 when carried out to meet the plan originally 

 proposed, will be extended into an astronomical triangu- 

 lation, which must, necessarily, take the place of the 

 primary triangles in geodetic work, pure and simple, as 

 applied by the Coast Survey in this country and by sev- 

 eral surveys organized by the leading Governments of 

 Europe. A large portion of our Western territory is 

 covered with mountain forms, of wuich little is known, 

 and presenting physical obstacles of such, great magni- 

 tude as not to permit at present the slow and tedious 

 operations of the primary trianguliitiou prior to the 

 commencement m skeleton aloue,.of the final map. The 

 secundary triangulatiou, having stations at prominent 

 mount a in peaks, and located in part from bases measured 

 at the astronomical stations and from the prosecution 

 ot thw trigoiiometrie work, gives us points that hereafter 

 may become vertices of a series of primary triangles 

 for which some day the country may call. At each of 

 these stations the true meridian of the place is estab- 

 lished. Each of these lines havintr a known azimuth, will 

 be of important use to the local surveyors and to the en- 

 gineers of railroads and other corporations in clieckiiiLr 

 their lines of survey made for specified .urposes. They 

 will also be, useful in determining the annual and <n her 

 fluctuations of the magnetic needle an (dement enter- 

 Ing so largely into the record that gives a title to lands. 



In flue tune the standard meridians used by the 

 public surveys, carried respectively from the 

 Valley of the Mississippi westward, and from the 

 1'aeirtc coast eastward, may bo adjusted to these 



geographical positions a matter of no little importance. 

 At most of these stations substantial stone monuments, 

 constituting observing piers, have been established, and 

 can always be identified. This branch of surveys being 

 the first and most necessary, after it shall have been 

 prosecuted with vigor, as it will be. for several years by 

 different parties of the War Department, the necessary 

 data will ultimately be available, so that the accumu- 

 ated material from a variety of sources, both public and 

 private, may be aggregated upon the sjeueral map of the 

 country, which is constantly revised at the Engineer De- 

 partment, and also upon maps of the geographical mili- 

 tary departments of the West, now in process of compila- 

 tion at the Engineer Office, Headquarters of the Army. 

 Astronomical observations for minor checks upon topo- 

 graphical work are conducted by officers of the corps of 

 engineers, who have also the executive charge of the 

 moving field parties. The mass of geographical posi- 

 tions already gathered, having prominent natural and 

 other objects for their initial points, will soon be pub- 

 lished. 



TOPOGRAPHICAL WORK. 



The present survey was first undertaken while the 

 officer now in charge was on duty upon the staff of Bre- 

 vet Major-Gen. E. O'C. Ord, then commanding the mili- 

 tary Department of California, to which duty ho was 

 assigned in the Fall of 1868. In the Sprius of 1869 the ex- 

 pedition for the recounoisanco in South-Eastern Ne- 

 vada, then an almost terra incognita, was organized 

 under the authority of the late Major-Gen. Geo. H. 

 Thomas, commanding the Military Division of the Pa- 

 cific. 



Since the expedition of Capt. Timpson in 1839. from 

 Great Salt L:ike to Virginia City, no military parties or- 

 ganized for survey of the Western interior had been in 

 the field with the exception of the survey of the 40th 

 parallel, Clarence King in charge, who had begun these 

 surveys in 18G7. At the breaking out jf the war, the 

 Corns of Topographical Engineers, to which had been 

 intrus t od prior to this dare this class of duties under the 

 Government, was taken from these and other workf of 

 a similar character, and sent with the armies in the 

 field. Duriusr tho war this class of interior surveys re- 

 mained dormant. 



After tho war, engineer officers were detailed at tho 

 headquarters of the several military departments and 

 were called upon to carry out surveys of various kinds. 

 The amount of money allotted was very small, and it was 

 impossible to tro to the expense of assistants other than 

 in the astronomical and topographical branches of the 

 work, where ability tor scientific mapping of the results 

 is a prerequisite. This recouuaisanco occupied the entire 

 season of 18C9, and its results were reduced at the ofhVo 

 in ban Faueiseo. A preliminary report and maps were 

 published for the use of the Military Department ot 

 California, and another map, upon a scale of one inch to 

 to twelve miles, was made for the uses of the War De- 

 partment. The final report of this expedition is now 

 completed. 



Tho officer in charge, having changed his station to 

 Washington, D. C., commenced in the early Spring of 

 1H71 the organization of a large expedition to take tho 

 lield that year. The several field parties left tho Central 

 Pacific Kailroad at Carliu and Battle Mountain, Nov., 

 moving in a southerly direction, closing their labors at 

 the end of the season at Tucson, Ari'/ona. In many 

 respects this was one of the most extraordinary expedi- 

 ditions that ever entered our Western territory; its 

 duties were both on the water and the land. A separate 

 or sub expedition ascended the Colorado River from 



