| Year | 1919 |
| Date | 17-Jul |
| Volume | 41 |
| Issue | 951 |
| Page | 57 |
| Category | Electrical |
| Part | |
| Title | The Electrical Transmission of Photographs |
| Author | Marcus J.Martin |
| Notes | 4. Prof. Korn's Selenium Machines. Arrangement, a selenium cell, wiring diagram, modern selenium cell, type adopted by Mercadier, receiving instrument, sensitive galvanometer, specimen of photo-telegraphic work, synchronising, frequency meter |