Letter (Astounding, February 1939): Lines of Force May Be Imaginary, But the Concept Works, So There's Something Real Behind It. Lines of Force from a Magnet May Not Be Tangible, But Generators Calculated on That Basis Produce Tangible Power.
| First published | February 1939 |
|---|---|
| Type | Essay |
| Date | Publication | Publisher | Type | Page | |
|---|---|---|---|---|---|
| February 1939 |
|
Astounding Science-Fiction, February 1939 | Street & Smith Publications, Inc. | MAGAZINE | 155 |