Filings coherer, Lodge-Muirhead system, patented 1
Filings coherer, Lodge-Muirhead system, patented 1901, with arrangement for adjusting the compression of filings by using an external magnet to turn the head of a screw inside the tube. Adjustment washer inside the tube marked in handwriting ‘Dec 31 1902’.
- Radio Communication
- Northampton Polytechnic Institute