| RefNo | PP/10/13/3 |
| Previous numbers | PP/42/13 |
| Level | Item |
| Title | Diagram, 'Electrical phosphoroscope. Commutator. Full size' by William Crookes |
| Date | 1887 |
| Description | A diagram, labelled figure 1B, showing an elevation plan of the commutator of Crookes's electrical phosphoroscope with parts labelled g-m. Crookes describes the phosphoroscope as '[consisting] of an opaque disk, a b e, 20 inches in diameter, and pierced with twelve openings near the edge as shown. By means of a multiplying wheel, d, and band, e f, the disk can be set in rapid rotation. At each revolution a stationary object behind one of the apertures is alternately exposed and hidden twelve times. A commutator, g [...] forms part of the axis of the disk. The commutator is formed of a hollow cylinder of brass round a solid wooden cylinder. The brass is cut into two halves by a saw cut running diagonally to and fro round it, so as to form on each half of the cylinder twelve deeply cut teeth interlocking, and insulated from these on the opposing half -cylinder by an air space about 2 mm across.'
Subject: Scientific apparatus and instruments
A print of this diagram was published in volume 42 of the Proceedings of the Royal Society alongside the paper 'On radiant matter spectroscopy:—Examination of the residual glow'. |
| Extent | 1p |
| Format | Diagram |
| PhysicalDescription | Ink and graphite pencil on paper |
| Digital images | View item on Science in the Making |
| AccessStatus | Open |
| RelatedMaterial | DOI: 10.1098/rspl.1887.0022 |
Fellows associated with this archive
| Code | PersonName | Dates |
| NA8188 | Crookes; Sir; William (1832 - 1919); chemist and science journalist | 1832 - 1919 |