—, —, rotary multiplier, xxxviii, 339.f
—, J. Henry, on the application of, to electro-magnetic apparatus, xix, 400.f
—, J. Locke, notice of a new, xxvi, 103f, 378.f
—, —, large thermoscopic, xxxiii, 365.
—, J. P. Emmet's, new form of, xxvi, 311.
—, C. G. Page, on the use of, xxxii, 354.f
—, —, astatic or rotary, xxxiii, 376.f
—, —, axial, xlix, 136.f
—, —, circular, xxxv, 259.f
—, modified, W. B. and H. D. Rogers, xxvii, 39.f