| Year | 1933 |
| Date | 07-Dec |
| Volume | 69 |
| Issue | 1,700 |
| Page | 539 |
| Category | Horology |
| Part | |
| Title | A Compensated "Invar" Rod Pendulum |
| Author | Geo. Gentry |
| Notes | The general proportions, details, the bob, front view, further small details, compensation, details, a point about circular error |