| Year | 1926 |
| Date | 10-Jun |
| Volume | 54 |
| Issue | 1,309 |
| Page | 553 |
| Category | Electrical |
| Part | 4 |
| Title | On Electrical Condensers |
| Author | Capt. Q.C.Crauford |
| Notes | Conventional diagram of thermionic valve, author's modified conception, fake amplifier for rendering contact audible, magnified previously imperceptible sound |