16 TBI ANGULATION AND SPIRIT LEVELING [bull. 175. 
the Chickasaw Nation was provided for in the act approved June 6, 
1897, Avhich appropriated $141,500 for this purpose. 
The total amount appropriated for surveys in Indian Territory, 
which included the lands of the Cherokees, Creeks, Choctaws, and 
Seminoles, was $530,000, which added to the amount provided for the 
resurvey of the Chickasaw lands amounts to $671,500. 
The total number of miles of standard, township, and subdivision 
lines surveyed, from the inception of the work to its completion in 
June, 1898, was 63,881. The topographic mapping completed at the 
same time covered an area of 30,885 square miles; in connection with 
which 133 triangulation stations were established, 9,303 miles of spirit 
level and 8,594 miles of vertical angles were run, and 920 permanent 
bench marks were located. 
TRIANGUIjATKXtf. 
The base for the triangulation was measured in April, 1895, on the 
railroad tangent which passes through Savanna, a station on the Mis- 
souri, Kansas and Texas Railway, the northern end of the base being 
about three-fourths of a mile north from Savanna station and 7 
miles south from South McAlester. This base was measured twice 
with a 300-foot steel tape under a tension of 20 pounds, and the 
temperature of tape determined at each tape length by reading three 
thermometers. The difference of the two measures (when corrected 
for difference in temperature) was 0.03 feet. 
The resulting length of base, when corrected for temperature, 
inclination, and reduced to sea level, is 24,893.451 feet, log. meters= 
3.8800962. 
Stations in the expansion were selected on the wooded ridges to the 
eastward and signals from 25 to 40 feet high erected. The lines 
between these stations formed bases for the main triangulation, which 
in 1895 was extended 45 miles southward and 110 miles northward from 
the base. The triangulation south of Savanna was executed by Mr. 
S. S. Gannett in May and June, 1895, the triangulation north of Savanna 
to the Kansas line by Mr. C. F. Urquhart during 1895, 1896, and 1897. 
Mr. Urquhart also extended triangulation over the Chickasaw 
Nation between February and June, 1898. Mr. H. L. Baldwin, jr., 
controlled the eastern portion of the Choctaw Nation in 1897. Trian- 
gulation was extended into Grayson County, Texas, by Mr. Jeremiah 
Ahern during the latter part of the season of 1898. 
The total number of stations occupied by the various observers was 
133, the greater number being occupied by Mr. Urquhart. 
The instruments used were Fauth theodolites, each having a circle 8 
inches in diameter and reading by micrometer microscopes to 2" of arc. 
In most cases the theodolite was elevated from 25 to 60 feet, in order 
