| Year | 1931 |
| Date | 26-Mar |
| Volume | 64 |
| Issue | 1,559 |
| Page | 303 |
| Category | Petrol Engine Topics |
| Part | |
| Title | A Design for a Compound Petrol Motor |
| Author | Elmer T.Wall (Chicago) |
| Notes | Part sectional elevation of early 3-cylinder compound petrol engine, latest 2-cylinder 30 c.c. two-stroke petrol engine |