| RefNo | AP/34/10/18 |
| Level | Item |
| Title | Unpublished figure, 'Examined without the selenite stage but in polarised light by rotating a crystal through the whole circle of 360 degrees' by William Bird Herapath |
| Creator | Herapath; William Bird (1820-1868); English surgeon; chemist |
| Date | 19 January 1854 |
| Description | A figure in black and red ink, labelled figure 30, showing a circle split into 16 segments. Arrows around the circle show the direction of the 'arc of double refraction'.
Subject: Chemistry / Optics |
| Extent | 1p |
| Format | Drawing |
| PhysicalDescription | Ink on paper |
| AccessStatus | Open |