| Reference number | NLB/61/154 |
| Alternative reference number | NLB/61 p93 |
| Level | Item |
| Title | Copy letter from Frederick Harrison, Assistant Secretary of the Royal Society; to Sidney F. Walker Esquire; 2 Richardson Avenue, Combe Down, Bath |
| Date | 25 May 1921 |
| Description | Informs Mr. Sidney F. Walker that Sir William Crookes read a paper just before the war on 'Eye-preserving glass for spectacles'. Explains that, according to Crookes, the glass was to be such as would cut off the invisible rays at both ends of the spectrum, as well as heat radiation. Notes that the paper is obtainable at 1/6d from their offices. |
| Extent | 1p |
| Format | Carbon |
| Access status | Open |