| Year | 1930 |
| Date | 10-Jul |
| Volume | 63 |
| Issue | 1,522 |
| Page | 26 |
| Category | General |
| Part | |
| Title | Recent Technical Progress |
| Author | |
| Notes | Contacts in long-distance telephony, a solar oil cooking plant, the Junkers "G.38" aeroplane, "no-load" working time of a 'bus, three-conductor electric cables |