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Show 12 Those determined by other astronomical methods, triangulation, and trigonometrical processes, from the years 1869 to 1874 inclusive, will appear in the form of condensed tables of geographical positions, altitudes, , distances, magnetic variations, & c, the mauuscript for which is in course of preparation. Connection was had with a point selected at the camp of organic zation of the expedition of 1874 with the monument at South Pueblo/ Colo., and the trial sextant- observations for latitude, here made by the; officers in charge of parties, were compared. \ The finished appurtenances and the necessary repairs to the observa- 4 tory have been completed, excepting the middle room and the dome, fori which a moderate sum should be authorized as soon as the same can be 1 made available. « I have also to recommend that a room adjoining the middle room to the north shall be constructed for the purposes of meteorological obser- | vations and storage of instruments. \ As has been customary, the several officers of the Corps of Engineers and of the line of the Army in charge of parties have made observations I for time and latitude at proper points, computing the observations in f the Office in Washington, D. C, upon their return from the field. No additional points have presented themselves where telegraphic connec- j tions for comparison with sextant and chronometer observations for ! time and latitude could be employed, but it is intended to perfect the methods, whereby, with themost portable instruments and with the proper accessories, determinations for longitude and latitude can be made sufficiently accurate to serve as initial points for measured and developed bases, at points remote from present routes of convenient transportation. When the telegraph now in process of construction, under the Signal- Service of the War Department, from Santa F6, N. Mex., to San Diego, Cal., via the Eio Grande, Camp Grant, and Tucson, Ariz., and ' Fort Yuma, Cal., is completed, convenient points, to be thus occupied, will be selected. The quadrilateral telegraphic communication, which will extend from Ogden, Utah, by Central Pacific Railroad, to San Francisco, Cal.; thence, via Southern Pacific Railroad or Coast Line, to San Diego, Cal.; thence, via Tucson, Ariz., to Santa F£, ST. Mex.; thence to Denver, Colo.; thence to Cheyenne, Wyo.; and thence, via Union Pacific Railroad, to close the circuit at Ogden, will be taken advantage of to check astronomic determinations at specific points that have been, or may be, occupied . on that part of the line extending from San Diego, Cal., to Santa F6, N. Mex. It is advisable, in furtherance of this most important class of work of the survey, to select at once at least two locations, one to be near the east base of the Rocky Mountains, another to the west of the Sierra Nevada, and both to the south of the fortieth parallel, at which the foundations for permanent field- observatories, similar to the one at Ogden, shall be laid at an early day. 1 have to recommend for the first Denver, Colo., and for the second Los Augeles or San Diego, Cal. GEODETIC ASD TOPOGRAPHICAL. Measured and developed bases, each connected with the belts of triangles that reach from Denver, Colo., on the north, to SautaF£, N. MexM on the south, and extend from the east base of the Rocky Mountain ranges to near the western boundary of Colorado and New Mexico, have |
