205 



Sneffels 2.04 miles, and from station 32 3.75 miles. The fall is 5,050 feet. 

 This difference of level is checked by sights to distant points to the- 

 south of station 32. These two cases are admitted, because the distances 

 were so short as to preclude the possibility of any considerable error. 



From all these results a table was made out, showing the heights of 

 each station above or below a common datum-point. Sultan Mountain 

 was selected to perform this latter function, from its central location, 

 and also from the fact that it was situated on the great central chain of 

 levels at its junction with the two principal sublines. 



A second column was added, giving the height of each station as deter- 

 mined by the single barometric reading taken thereon. A third column 

 was made out by means of the first two by adding the number in the first 

 column to the one in the second when preceded by the minus sign, and by 

 subtracting it when plus. This column now represents the elevations 

 above sea-level of Sultan Mountain, as determined from the barometric 

 readings at the several stations. It will be seen that the twenty-three re- 

 sults have a range of 203 feet. A mean of all these was assumed as the true- 

 height of Sultan Mountain, and by reversing the previous process and 

 adding the plus differences of height in the first column and subtracting 

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

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

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

 tions. 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 readings give heights above the mean, and the later below it. 

 Whether this is merely accidental or due to some physical law, I cannot 

 tell. It will be seen that several of those 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 storms or other 

 causes, we failed to get barometric readings. 



Name of station. 



Station 5 



Station 8 



Uncompahgre Peak . . 



Station 10 



Station 11 



Station 13 



Handie's Peak 



Station 16 



Rio Grrande Pyramid. 



Sultan Mountain 



Silverton 



Station 27. 



station 29 



Station 30 



Station 32 



Mount Sneffels 



Station 34 



Mount Wilson 



Station 36 



Station 37 



Station 38 



Station 48 



Station 51 



Mean 



o a 



—629 

 —511 

 +869 

 —223 



—2, 755 

 —544 

 + 631 

 + 175 

 +407 

 



—3, 961 

 —777 

 —160 

 +531 



—4, 258 

 + 792 

 —369 

 + 914 



. —812 

 —718 

 —320 



—1,061 

 —835 



12, 770 



12, 960 

 14, 337 



13, 082 

 10, 684 



12, 895 



14, 101 



13, 593 

 13,801 

 13, 298 



9,377 



12, 491 

 13, 120 



13, 927 

 9, 027 



14,162 

 12, 988 

 14,135 

 12, 538 



12, 623 



13, 014 

 12, 321 

 12, 518 



13, 399 

 13,471 

 13, 468 

 13, 305 

 13, 439 

 13, 439 

 13, 470 

 13,418 

 13, 394 

 13, 298 

 13, 338 

 13, 268 

 13, 280 

 13, 396 

 13, 285 

 13,370 

 13, 357 

 13,271 

 13, 350 

 13,341 

 13, 334 

 13, 3(^2 

 13, 353 



13, 366 



12, 737 

 12, 855 

 14, 235 

 13, 143 

 10,611 



12, 822 



13, 997 

 13,541 

 13, 773 

 13,366 



9,405 



12, 589 

 13,206 



13, 897 

 9,108 



14, 158 

 12, 997 



14, 280 

 12, 554 



12, 648 



13, 046 

 12, 305 

 12, 531 



1874. 



Aug 



Sept. 



Oct. 



