. Reports upon the survey of the boundary between the territory of the United States and the possessions of Great Britain from the Lake of the woods to the summit of the Rocky mountains . elescope, which would often sud-denly indicate large changes in the adjustments that could not be detectedby means of the striding-level. The instrument Avas, in fact, faulty to adegree that rendered the attaimnent of precise results with it was soon discarded and replaced by No. 20, which was used at sixteenstations and at Fort Buford, and found to be, in all respects, a perfectinstrument. I N
. Reports upon the survey of the boundary between the territory of the United States and the possessions of Great Britain from the Lake of the woods to the summit of the Rocky mountains . elescope, which would often sud-denly indicate large changes in the adjustments that could not be detectedby means of the striding-level. The instrument Avas, in fact, faulty to adegree that rendered the attaimnent of precise results with it was soon discarded and replaced by No. 20, which was used at sixteenstations and at Fort Buford, and found to be, in all respects, a perfectinstrument. I N S T K C M E N T - S T A X D S . From the beginning of the work up to Station No. 5, the instrumentswere mounted upon wooden ])osts, about twenty inches in diameter and sixfeet long, sunk four feet in the ground. Well-seasoned logs were selected, BOUNDARY COMMISSION IINSTRUMiNT STAND) DEVISED BY CAP^ Corps of h Sc&l bill- 0 Owck scj-eir d /Laiwed. Je/ralt screw e. Ruhlvf \vashcr rf IabU bolts h of oaJt jrA le inn-k k PU/L ef &lAnouljLJ- aaJc Jrd/ne. 1 Opcii. steel ?d^nip!,in Oak tdbU n OuHjici iron iic^^ jm- LjljHinoJ> Wnnch. REPORT OF THE CHIEF ASTRONOMER, APPENDIX A. 289 and the portion above gi-ound painted to prevent swelling, shrinking, andtwisting with atmospheric changes. They served their purpose very well,but as our field of labor was, for the most part, a treeless country, it wasvery desii-able to have some sort of a stand which could be convenientlytransported from station to station. Such an one was devised by CaptainTwining, and manufactured to his order at the Detroit Locomotive pointed steel bars, two inches in diameter and six and a half feetlong, were driven four and a half feet into the ground, and formed a part ofa rigid system, with a braced triangular frame-work of oak, twenty-nineinches high, whose horizontal section was an isosoles triangle, of aboutfourteen inches base. The connectidn between the
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Keywords: ., bookcentury1800, bookdecade1870, bookpublisherwashingtongovtprin
