‎Ming Tsao‎
‎The moving force‎

‎A Note on experiments with floating Magnets showing the motions and arrangements in a plane of freely moving bodies, acted on by forces of attraction and repulsion" and serving in the study of the directions and motions of the lines of magnetic force...‎

‎(New Haven), 1878. Both issues with modern blank wrappers. In: The American Journal of Science and Arts"", Third series Vol. 15, No 88 and Vol. 16, No. 94. Pp. 245-524 and pp. 247-334 (2 entire issues offered). Mayer's papers: pp. 276-277 with textfig., pp. 247-256 with 2 pp. of illustrations.‎

‎First appearance of the papers in which Mayer describes his invention of the method of floating tiny magnets in a magnetic field, used in the early twentieth century as a key to discovering or illustrating atomic structure.""Mayer is most remembered (and cited) for his experiments in which magnetized needles were inserted into corks, which were then ftoated on water with their south poles upward, under the north pole of a powerful electromagnet. Under these conditions, certain definite stable configurations were observed “which suggested the manner in which atoms of molecules may be grouped in the formation of definite compounds and which illustrated various properties of the constitution of matter. These experiments won high praise from Kelvin ... and were later used by J. J. Thomson (Electricity and Matter [New Haven, 1904], ... and others as a key to the way in which a characteristic number of electrons might be arranged within the atoms of each chemical element in relation to the periodic table. Mayer thus made a small but significant contribution to the theory of atomic structure."" (DSB)Issue 94 of vol. 16 contains an importent paper by HENRY A. ROWLAND ""Research on the Absolute Unit of Electrical Resistance"", pp. 281-291, in which he established an authoritative figure for the absolute value of the Ohm. - Wheeler Gift: 3967.‎