H. F. Joel and Co
Henry F. Joel and Co of Wilson St, London EC.
The Pilsen lamp was developed by two Austrian engineers, Ludwig Piette and Franz Krizik, and was marketed in Britain by Henry Francis Joel. It had a complex regulating mechanism which used an iron core between two solenoids. The lamp was quite extensively used, and won a Gold Medal at the Paris Electrical Exhibition of 1881
1882 The Joel lamp was a semi-incandescent lamp (i.e. avoiding the need for a vacuum enclosure). By this time it was in use at the Prudential Assurance Company's building in High Holborn and at the Admiralty's dockyards at Chatham and Portsmouth as well as lighting the Pompeian Court at the Crystal Palace. It too was available from the Pilsen-Joel and General Electric Light Co.
1891 Developed an "engine-dynamo"
1892 Crystal Palace Electrical Exhibition. Electrical motors and dynamos. 
1894 Catalogue of dynamos, storage batteries, arc lamps and other apparatus 
Sources of Information
- IET Arc lamp exhibition 
- The Standard, September 27, 1882
- The Times, May 16, 1882
- 1892 The Practical Engineer
- The Engineer