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Show APPENDIX NN. • 1257 APPENDIX C. EXECUTIVE AND DESCRIPTIVE REPORT OF LIEUTENANT THOMAS W. SYMON£, CORPS OF ENGINEERS, ON THE OPERATIONS OF PARTY NO. 3, CALIFORNIA SECTION, FIELD SEASON OF 1876. UNITED STATES ENOINEKR OFFICE, GEOGRAPHICAL SURVEYS WEST OF THE 100TH MERIDIAN, Washington, D. C, April 15, 1877. SIR: I have the honor to snbnit herewith the executive report of Party No. 3, California section of the survey, for the field season of 1876, together with a brief report on the mining interests of the Coma took lode. EXECUTIVE REPORT. The duties assigned to the party under my charge were to lay out and measure a base- line, and develop it for the use of the outlying parties in the vicinity, and after this was done to commence work on a detailed* map of the country embraced by the mining interests of Virginia City, Nev., and the neighboring district. I arrived in Carson City, Nev., August 23, 1876, and after making the necessary preparations and procuring supplies, laborers, instruments, & c, started by wagon, August 28, for the valley of the Carson River, near Sutro, whither Dr. Kampf and Mr. Karl had preceded qie to select a place for the base- line. On arriving in the valley camp was made on the banks of the Carson River, and as it was to be permanent for some time, we made it as comfortable as possible. The base- line was laid out on a very straight portion of the old emigrant road through the valley, aud the work of development immediately commenced. On the 4th of September the party was joined by Mr. Louis 8eckels, and on the 10th of the same month by James Bullock and an ambulance and team. The party now consisted of Second Lieut. Thomas W. Symons, Corps of Engineers, executive officer and field astronomer; Dr. F. Kampf, astronomer; Mr. Anton Karl, topographer; Mr. Louis Seckels, meteorological observer; Mr. Simon B. Cameron, aneroid and odometer recorder; James Bullock, teamster, and John Rafferty, cook. The base development being finished, the party separated, Dr. Kampf remaining at Sutro to measure the base. In this he was assisted by Mr. Seckels and three hired laborers. The apparatus used in the measurement is the invention of Dr. Kampf, and consisted of a wooden rod with finely- graduated scales at both ends, and at the center an apparatus for determining its deviation from the horizontal, and three iron stands with nickel tops, on each of which was engraven a fine Line, this line being the initial point of each successive measurement with the rod. Comparisons of the rod were made every morning and evening with the standard rods of the United States Coast Survey, and the reading of the rod corrected for temperature. A full account of the apparatus, the mode of its use, and the results obtained, will be found in the report of Dr. Kampf. On September 16 I went to Virginia City, with Mr. Karl as topographer and Mr. Cameron as meteorological observer, and the necessary laborers, and commenced work on a detailed contour map of the city and vicinity. This work was done with the plane- table, and the method pursued was the following: A number of points were selected whose projections would occupy different points on the plane- table sheet, and these were occupied with the trausit, and their positions carefully computed ia reference to the base and the monument points used in its development. These points then being laid down on the plane- table formed the foundation for the detailed work, which was done by Mr. Karl. Other points were occupied with the transit during the time that the sheet was being filled iu, and these, together with cross- sight stations, being computed, formed checks which were continually applied to the plane- table work. At each of the points occupied by the plane- table, and at many others, as hills, ravines, canons, road- crossings, saddles, mesas, & c, barometric observations were taken for altitude, which, beiug referred to synchronous observations taken in camp under the same natural existing circumstances of atmospheric pressure, temperature, and humidity, gave very accurate relative altitudes, and the altitude of the camp, being determined by a long series of observations, enabled us to determine the elevations of all the poiiits above mentioned above the sea- level very accurately. Besides the barometric readings, elevations to well- determined points were read from the vertical limb of the trausit and from the alidade of the plane- table, and level- lines run with the T- level. From these data the contours are being put in in the office of the survey at Washington. The constant aim has been to secure the greatest accuracy and to leave no natural featnre of the surface or work of any importance unrepresented, and Mr. Karl, for bis intelligent devotion to the work and his care and accuracy, deserves the greatest credit. Three plane- table sheets were filled in, two to a scale of 1,000 feet to an inch, and one to a scale of 500 feet to an inch, the larger scale being used in delineating that portion of the country including Virginia City. The country gone over includes Virgiuia City and the northern portion of the Comstock lode, the country to the north and west |