Filings coherer, glass tube bent into U-shape at one end with bulb to form side-pocket on mounting bracket with terminals, 1894-1904 1894-1904
Filings coherer, small glass tube with bulb at one end and cap of red sealing wax at other end, 1898 1898
Receiving ‘jigger’ or oscillation transformer with single layer split secondary coil and superimposed moveable two-part primary coil, used by the Marconi Company, probably made by Marconi's Wireless Telegraphy Company, Chelmsford, Essex, England, 1899 Receiving ‘jigger’ used by the Marconi Company, 1899 1899