734 



BULLETIN UNITED STATES GEOLOGICAL SURVEY. 



number im the first column to the one in the second when preceded by the 

 minus sign, and by subtracting it when plus. This column represents the 

 elevations above sea-level of Sultan Mountain as determined from the 

 barometricreadings at the several stations. It will be seen that the twenty- 

 three results have a range of 203 feet. A mean of all these was assumed as 

 thetrue heightof Sultan Mountain ; and by reversingthe previous process 

 and adding the plus differences of height in the first column and subtract- 

 ing the minus, a fourth column was obtained, giving the elevation of each 

 station as reduced from the mean of the twenty -three readings. A fifth 

 column was added, giving the date of each reading on the different 

 stations. From this it will be seen that the observations extend from 

 August 1 to October 6 — more than two months. By examining the table 

 carefully it will be seen that nearly all the earlier i"eadiugs give heights 

 above the mean and the latter below it. Whether this is merely acci- 

 dental, or due to some physical law, I cannot tell. It will be seen that 

 several of these stations, whose height relative to the rest has been 

 well determined, do not appear in the table. This is due to the fact that 

 at those stations, either from storuis or other causes, we failed to get 

 barometricreadings. 



'Name of station. 



' Station 5 



' Station 8 



'Uncompahgre Peak . 



'Station 10 



'Station 11 



'Station V.i 



' Haidie's Peak 



' Station 16 



'Eio Grande Pyramid. 



'Sultan Mountain 



' Silverton 



' Station 27 



' Station 29 



' Station :}0 



' Station 3-.^ 



'Mount Snetfels 



' Station 34 



' Mount Wilson 



' Station 36 



' Station 37 



' Station 38 



' Station 48 



'Station 51 



'Mean. 



Aug. 

 Aug. 

 Aug. 

 Aug. 

 Aug. 

 Aug. 

 Aug. 

 Aug. 

 Aug. 

 Aug. 

 Aug. 

 Sept. 

 Sept. 

 Sept. 

 Sept. 

 Sept. 

 Sept. 

 Sept. 

 Sept. 

 Sept. 



Sept. 



Sept. 

 Oct. 



1, 1874. 

 6, 1874. 



8, 1874. 

 10, 1874. 

 12, 1874. 

 14, 1874. 

 15, 1874. 

 17, 1874. 

 22, 1874. 

 31,1874. 

 31,1874. 



3, 1874. 



4, 1874. 



6, 1874. 



9, 1874. 

 10, 1874. 

 U, 1874. 

 13, 1874. 

 14, 1874. 

 1.5, 1874. 

 20, 1874. 

 30, 1874. 



6, 1874. 



" With the elevations of these stations detei:mined, the heights of un- 

 visited points were obtained by applying the difference of level as ob- 

 tained from the vertical angle to the height of the station from which 

 the angle was taken. As most of the un visited points are sighted from 

 many stations, we have for each a number of determinations, of which 

 the mean is taken. Many of these points are quite as well determined 

 as some of the stations." 



