| RefNo | AP/36/17/1 |
| Level | Item |
| Title | Unpublished manuscript, 'On the relation of the angular aperture of the object glasses of confirmed microscopes to their penetrating power and to oblique light' by J W Griffith |
| Creator | Griffith; J W (fl 1854) |
| Date | 1854 |
| Description | Griffith writes that it is known that delicate markings on a transparent object, such as the valve of a Gyrosigma, may be rendered more distinctly visible by using an object-glass of large aperture, by bringing the mirror to one side, and by placing a central stop in the object-glass or the condenser or in both; the increased distinctness produced in these several ways being due to the illumination of the object by oblique light. Experiment also shows that the degree of obliquity of the light requisite varies with the delicacy or fineness of the markings, being greater as these are more delicate; so that the finest markings require the most oblique light which can possibly be obtained to render them evident, and the angular aperture of the object-glass must necessarily be proportionately large, otherwise none of these oblique rays could enter it.
Annotations in pencil and ink throughout. Includes two figures in the text of rays of light.
Subject: Optics
Received 29 April 1854. Communicated by Arthur Henfrey.
Whilst the Royal Society declined to publish this paper in full, an abstract of the paper was published in volume 7 of the Proceedings of the Royal Society as 'On the relation of the angular aperture of the object-glasses of compound microscopes to their penetrating power and to oblique light'. |
| Extent | 17p |
| Format | Manuscript |
| PhysicalDescription | Ink on paper |
| AccessStatus | Open |
| RelatedMaterial | DOI: 10.1098/rspl.1854.0018 |
Fellows associated with this archive
| Code | PersonName | Dates |
| NA3844 | Henfrey; Arthur (1819 - 1859) | 1819 - 1859 |