RT Journal Article SR Electronic T1 The isodynamic surfaces of the compound pendulum JF American Journal of Science JO Am J Sci FD American Journal of Science SP 22 OP 26 DO 10.2475/ajs.s3-31.181.22 VO s3-31 IS 181 A1 Nipher, F. E. YR 1886 UL http://www.ajsonline.org/content/s3-31/181/22.abstract AB