RT Journal Article SR Electronic T1 A method for determining the flexure of a telescopic tube for all positions of the instrument JF American Journal of Science JO Am J Sci FD American Journal of Science SP 374 OP 376 DO 10.2475/ajs.s3-23.137.374 VO s3-23 IS 137 A1 J. M. Schaeberle YR 1882 UL http://www.ajsonline.org/content/s3-23/137/374.abstract AB