| Year | 1920 |
| Date | 17-Jun |
| Volume | 42 |
| Issue | 999 |
| Page | 560 |
| Category | Electronic |
| Part | 4 |
| Title | The Action of the Wireless Telephone |
| Author | R.A.Mallet |
| Notes | Using the potentiometer to give grid +ve or -ve potential, the "Audion" circuit with valve used as a detector, Audion circuit with reactance, circuit with Adion rectifier & one magnifying valve, method of winding a flat coil, coils for varying coulping |