拍品专文
John Marshall (1663-1725). Marshall originally worked from The Sign of the Gun in Ludgate, London, changing the name to The Archimedes and Two Pairs of Golden Spectacles in 1689. He developed the method of grinding a number of lenses simulataneously on blocks of the same size, having developed it from an idea in Hooke's Micrographia. He appears to have invented his Double Microscope or Great Double-Constructed Microscope around 1693, when he advertised it as "more useful than any yet have been." The microscope was first described fully in Harris' LexiconTechnicum of 1704.
Marshall's microscope incorporated many important features, including having the body-tube on a limb and pillar, the stage being on the same axis as the main body, the use of a condenser on a moveable arm, coarse and fine focusing, a fish plate and a graduated set of objectives. All these characteristics were incorporated into later microscopes.
No two surviving examples, either by Marshall or others, are exactly alike. This example has two characteristics which are of particular note. The first is the ivory body-tube. One in the Whipple Museum, Cambridge, has an ivory body-tube as well, but this is on an unusual seven-sided base and is dated as circa 1730, late for a Marshall-pattern. An example illustrated in Clay and Court on page 98 has a base very similar to this one. It appeared at a sale in 1918 at London auctioneers Puttick and Simpson and is attributable to Marshall or his sucssesor John Smith. It came from Norwich and had not been previously known.
The tooling on this example has motifs very similar to Turner numbers 20b and 49.
Marshall's microscope incorporated many important features, including having the body-tube on a limb and pillar, the stage being on the same axis as the main body, the use of a condenser on a moveable arm, coarse and fine focusing, a fish plate and a graduated set of objectives. All these characteristics were incorporated into later microscopes.
No two surviving examples, either by Marshall or others, are exactly alike. This example has two characteristics which are of particular note. The first is the ivory body-tube. One in the Whipple Museum, Cambridge, has an ivory body-tube as well, but this is on an unusual seven-sided base and is dated as circa 1730, late for a Marshall-pattern. An example illustrated in Clay and Court on page 98 has a base very similar to this one. It appeared at a sale in 1918 at London auctioneers Puttick and Simpson and is attributable to Marshall or his sucssesor John Smith. It came from Norwich and had not been previously known.
The tooling on this example has motifs very similar to Turner numbers 20b and 49.