—, chemical action in needles suspended from, xviii, 402.
—, best position of, for mutual action, H. Lloyd, xxxviii, 96.
—, current produced by the rotation of, Pixii, xxiv, 144, 146.f
—, electric spark from, J. Henry, xxii, 403.
—, a mode of producing sparks and galvanic currents from the horse shoe, J. P. Emmet, xxiv, 78.f
—, new method of making permanent, xxxvi, 335.f
—, galvanic, construction of, J. B. Zabriskie, xxxvi, 124.f
—, —, Henry's large, xix, 408.f
—, —, made for Laboratory of Yale College, xx, 201.
—, —, Humbert's, xxxviii, 204.