RT Journal Article SR Electronic T1 An improved wave apparatus JF American Journal of Science JO Am J Sci FD American Journal of Science SP 218 OP 219 DO 10.2475/ajs.s3-39.231.218 VO s3-39 IS 231 A1 John T. Stoddard YR 1890 UL http://www.ajsonline.org/content/s3-39/231/218.abstract AB