| Year | 2006 |
| Date | 27-Oct |
| Volume | 197 |
| Issue | 4,285 |
| Page | 518 |
| Category | General |
| Part | 94 |
| Title | Letters to a Grandson |
| Author | M.J.H. Ellis |
| Notes | Moves on to the practical application of optical interference. Michelson's interferometer, the evaluation of the metre in terms of wavelength |