RT Journal Article SR Electronic T1 On the effect of thin plates of iron used as armatures for electro-magnets, and a new form of induction coil JF American Journal of Science JO Am J Sci FD American Journal of Science SP 361 OP 364 DO 10.2475/ajs.s3-11.65.361 VO s3-11 IS 65 A1 John Trowbridge YR 1876 UL http://www.ajsonline.org/content/s3-11/65/361.abstract AB