BITTER ROOT FOREST RESERVE 389 



this point was determined. This work was performed by Mr S. S. 

 Gannett, who had the cooperation in the longitude work of Pro- 

 fessor H. S. Pritchett, then of the Washington University at St 

 Louis, and now Superintendent of the U. S. Coast and Geodetic 

 Survey. The latitude was obtained by circumzenith observations 

 on 56 pairs of stars, and the longitude by time observations and tel- 

 egraphic exchange of clock signals with St Louis on five nights. 

 The probable error of the results obtained for this position was 

 very small, so that it was certain within a few feet, the surface of 

 the whole terrestrial globe being taken into consideration. The 

 next process was to measure a base line one end of which would 

 be connected with the astronomic pier. This line was measured 

 along a tangent of the Northern Pacific Railroad. The total 

 length of it was 5.33 miles, and the difference between the two 

 measurements after all corrections had been applied was about 

 1 inch — that is, the probable error was about 1 : 338000 part of 

 the length. 



From this base line was expanded a system of triangulation, 

 which was executed with great care within certain limits, the 

 triangles closing with an average error of 2 seconds. Beyond 

 these it was extended as a reconnaissance survey, but it is be- 

 lieved that the results obtained will be entirely sufficient for 

 map-making purposes, although it will eventually be completed 

 in a more refined wa}^. The surveys were under the general direc- 

 tion of Mr E. C. Barnard, who was personally in charge of a 

 party engaged in the detailed mapping of the Bitter Root valley 

 and the adjacent mountains. He had as assistants in charge of 

 sub-parties Messrs J. B. Lippincott and H. S. Hackbusch. 



The bounding lines of this Reserve are defined in part by the 

 land lines of the public land system, none of which had been 

 surveyed. For the purpose of locating these boundaries and 

 also for establishing a basis from which other township and sec- 

 tion lines could be projected a special party, under Mr Hack- 

 busch, was organized, and the results of this work were the de- 

 termination and marking of the greater portion of the eastern 

 boundary. The existing law relating to the subdivision of the 

 public land requires that all linear measurements shall be made 

 with a chain, a method which in a heavily timbered and moun- 

 tainous country is very inaccurate and laborious. The men en- 

 gaged in this class of work encountered many hardships, ex- 

 hausted their physical strength, and were able to accomplish so 

 little at a large expense that the question of the feasibility of 



