Descriptive catalogue of magnetic, electro-magnetic, electro-dynamic, and magneto-electric inductive instruments and apparatus : constructed and sold by Watkins and Hill, 5 Charing Cross, London.

  • Watkins and Hill.
Date:
[between 1837 and 1851]
Catalogue details

Licence: Public Domain Mark

Credit: Descriptive catalogue of magnetic, electro-magnetic, electro-dynamic, and magneto-electric inductive instruments and apparatus : constructed and sold by Watkins and Hill, 5 Charing Cross, London. Source: Wellcome Collection.

    9/20 (page 7)
    57. Small Cylindrical Voltaic Battery, with fixed bent connecting wires, for illustrating the elementary experiments of electro-magnetic science. When the magnetic needle plays freely between the bent arms of the wire and the battery is excited, the electro-mag¬ netic effect is manifested by the deflection of the needle. The advantage of this com¬ bination consists in avoiding the use of mercury and the amalgamation of wires, 105. 6d. 58. Glass Tube and a copper wire coiled round it for magnetizing steel needles, by the in¬ duction of an electric current, 25. 6d. 59- Apparatus to show the magnetic powers acquired by a thick cylinder of soft iron (bent into the form of a horse-shoe), surrounded by a coil of copper wire transmitting an electric current. The properties of voltaic electrical induction are strikingly made mani¬ fest by this apparatus; for when the electric current traverses the copper wire the cylinder of soft iron becomes a magnet; but when the current no longer pervades the copper coil, and the armature is removed, the soft iron loses altogether its transient powers, and resumes its pristine indifference, 35. 6d., 5s., 6s. 6d., 15s., £1 10s. 60. Apparatus of larger dimensions to illustrate the magnetic force which soft iron exerts when under the influence of electric currents. It consists of a stout horse-shoe cylinder of soft iron, surrounded by many strands of insulated copper wire in short lengths. When the electric current is passing, the iron becomes powerfully magnetic, and supports by its armature many hundred pounds weight. The armature is supplied with a swivel hook or oval loop for the purpose of hanging on the weights, £3 35., £5 5s., £6 6s. 61. Apparatus to show the continued revolution of one pole of a magnet about a vertical wire transmitting a rectilinear current. The direction of rotation may be reversed by simply changing the direction of the electric current, £1 15. 62. Apparatus with Two Magnets. This instrument shows the opposite rotations of the oppo-