PRECISE LEVELING IN THE UNITED STATES, 1903-1907. 
7 
point on the Shreveport to Smithland line, subdivided a number of circuits in the 
southern part of the net and changed the elevations in that region materially. 
The fifth line, from Grafton to Chicago, Ill., together with a line run by the United 
States Geological Survey, from Pekin to Olney, divided the large circuit, Graf- 
ton-Savanna-Chicago-Mackinaw-Gibraltar-Cincinnati-St. Louis-Grafton, into three 
smaller circuits. The sixth line, from Grand Rapids to Aitkin, Minn., completed a 
small circuit. 
Second. The United States Geological Survey during 1905-6 ran five lines with 
an instrument of the same type as the Coast and Geodetic Survey level, described 
on pages 200-211 of Appendix 3, Report for w 1903. The aggregate length of these 
lines is 731 kilometers (454 miles), and they form parts of seven new circuits. The 
first and second are from Pekin to Champaign and from Olney to Champaign, form 
ing the line, Pekin to Olney, mentioned above. The third is from Portsmouth to 
Chillicothe, Ohio, connecting the Coast and Geodetic Survey leveling at Chillicothe 
with the leveling along the Ohio River. The fourth is from Chillicothe to Columbus, 
Ohio. The fifth is from Valley Crossing, a point on the fourth line, to Uhrichsville, 
Ohio, where it connects with the leveling of the Baltimore and Ohio Railroad, 
described in the next paragraph. 
Third. The Baltimore and Ohio Railroad furnished 1 031 kilometers (641 miles) 
of leveling to the level net. One line was a continuation of the work of 1902 * and 
extends from Foley, Pa., to Chicago Junction, Ohio. A section of this line, however, 
between Struthers and East Akron Junction, Ohio, was not used on account of 
checks indicating large errors or mistakes in it. The second line is from Warwick, a 
point on the first line, to Benwood, near Wheeling, W. Va. The third line is from 
Cumberland, Md., to Benwood, W. Va. The fourth line is from Washington, D. C., 
to Baltimore, Md., where it was connected by the Coast and Geodetic Survey with 
sea level. The fifth line is from Relay, Md., a point on the preceding line, to Wash 
ington Junction, Md., where it connects with the Baltimore and Ohio Railroad 
leveling of 1902* The Baltimore and Ohio Railroad thus furnished one large 
circuit and one small circuit of its own leveling and several connections with other 
leveling of the level net. 
Fourth. One line of wye leveling of the same class as the leveling along the 
Ohio River, described on page 347 of Appendix 3, Report for 1903, and run under 
the direction of the Corps of Engineers, U. S. Army, was added to the net. It 
extends from Zanesville to Marietta, Ohio, along the Muskingum River (122 kilo 
meters, or 76 miles) and furnishes a second connection between the United States 
Geological Survey new leveling and the Ohio River line. 
There have thus been added to the level net since it was adjusted in 1903, 
4 000 kilometers (2 500 miles) of leveling by the Coast and Geodetic Survey, and 
2 750 kilometers (1 700 miles) by other organizations. Of these lines, two lines in 
Minnesota and two in Louisiana, with a total length of 506 kilometers (314 miles), 
are spurs from the net. All other lines form links or parts of links of the net and 
are concerned in the adjustment. 
* See page 348 of Appendix 3, Report of the Coast and Geodetic Survey for 1903, “Precise Leveling 
in the United States.”