TOPOGRAPHICAL MAPS OF THE STATE. 24! 



of the observatory. The instrument used in the survey was a ten-inch 

 theodolite belonging to the Thayer School of Engineering, Dartmouth 

 college. The signals used were heliotropes, which were kindly loaned for 

 this purpose by the United States Coast Survey. 



Respectfully submitted, E. T. QUIMBY. 



GEODETIC CONNECTION SURVEY. 



DARTMOUTH COLLEGE, April i, 1874. 



DEAR SIR: I am instructed by the superintendent of the United States 

 Coast Survey to furnish you any information you may desire from the 

 results of the triangulation of New Hampshire. It is desired that you 

 state, in publishing these results, that they are obtained by the first rough 

 computations, and will doubtless be somewhat modified by the final 

 adjustments. I have occupied, for observations, twelve stations in the 

 three seasons which have been given to the work, and observations have 

 been made upon several hundred stations. By an appropriation made 

 by the state the work has been greatly facilitated and extended, in the 

 establishment of tertiary stations. The number of geographical posi- 

 tions already determined is fifty, the altitudes of which have also been 

 found by trigonometrical levelling. Besides these, many others have been 

 observed from one direction, and will only require observing from another 

 point to give their latitudes and longitudes. 



The accompanying chart shows the scheme of this triangulation and 

 the progress thus far, and the former Coast Survey stations with which it 

 is directly connected. The stations here shown are only those occupied 

 as points of observation, the tertiary points being too numerous to be 

 shown on a chart of this size. The base from which this triangula- 

 tion proceeds 'is the line Monadnock-Uncanoonuc. Although these 

 results, as above mentioned, are not to be considered final, it may be 

 remarked that the latitude and longitude of Gunstock, as computed 

 from the base Monadnock-Uncanoonuc, through this triangulation, differ 

 from the former results of the Coast Survey only oo".O3. From this it 

 would seem that the correction made by the final adjustment will not be 

 large. Respectfully yours, E. T. QUIMBY, 



Acting Assistant U. S. C. S. 



PROF. C. H. HITCHCOCK, State Geologist. 

 VOL. i. 33 



