RT Journal Article SR Electronic T1 Probable law of densities of the planetary bodies JF American Journal of Science JO Am J Sci FD American Journal of Science SP 393 OP 401 DO 10.2475/ajs.s3-38.227.393 VO s3-38 IS 227 A1 R. Hooke YR 1889 UL http://www.ajsonline.org/content/s3-38/227/393.abstract AB