Crystal Palace International Electric Exhibition 1881-82

21 j. Modem Plate Protector, with grooves. k. l. > Old forms of Protectors. m. j n. Varley’s Original Vacuum Protector. o. Varley’s Vacuum Protector (later form). p. Cable Lightning Protector, in use by the Post Office Tele- graph. Department, having in addition to plates a metallic bobbin, electro-nickel plated, in connection with, the earth. It is wound with a fine platinum wire covered with silk, and passed through melted paraffine wax, the wire being placed in the line circuit. The metallic bobbin is carefully lacquered to secure insulation in damp situations. Modern Plate Protector without grooves, in use by the Post Office Telegraph Department. [32.] INSULATORS. A Selection, of Insulators as used in England at different periods. C W. F. Cooke’s original goose- a. Iron wire. J quill insulator, which was used on b. Three-strand copper, j the line between Paddington and (_West Drayton, in 1838. c. Cook and Wheatstone’s original ring insulator (1840). d. Cone insulator, original form (1845). e. }) }) later ,, y, )} ,, form for repairing broken insulators. g. Walker’s double-cone insulator (brown). (1850.) h. „ „ „ (white). i. Physick’s insulator (1847), in which the bolt by which the wire is suspended is insulated by mastic cement in the cavity at the top of the insulator. j. Edwin Clark’s brown earthenware insulator, with, zinc cap (1850). k. Ditto, with groove for wire. l. Ditto, glass instead of earthenware. w. (1851) brown earthenware. h. „ glass. o. Latimer Clark’s invert insulator, corrugated (1856). p. Varley's double-cup insulator, fitted. g. Ditto, in separate parts, 1862. r. Varley’s No. 11 wire double-cup insulator. s. Brown earthenware insulator called (Z). t. Jobson’s invert white, double shed. u. „ „ single „