| Reference number | NLB/56/551 |
| Alternative reference number | NLB/56 p317 |
| Level | Item |
| Title | Copy letter from Robert William Frederick Harrison, Assistant Secretary of the Royal Society; to the Director of the Ordnance Survey |
| Date | 11 March 1919 |
| Description | Informs the Director of the Council's recommendation for their Magnetic Survey Committee: 'it is desirable to repeat a Magnetic Survey at periodic intervals and such repetition could be carried out with advantage by the Ordnance Survey Department under the advice of a Committee of the Royal Society.' |
| Extent | 1p |
| Format | Carbon |
| Access status | Open |