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MICROSCOPE-ANTIQUES.COM     © 2013-15.



 

ROTATING DISK-HOLDER FOR OPAQUE SPECIMENS:

c. 1865-1912

MAKER: R. & J. BECK

MODEL: 'OPAQUE DISK-REVOLVER'

DESCRIPTION HISTORY
 Microscope
Microscope Microscope
Microscope Microscope

DESCRIPTION:


beck revolver caseThe 'revolver' is designed to sit on top of the microscope stage and consists of a brass plate with a large opening and a mechanism to facilitate observing small opaque objects by allowing them to be rotated and viewed from different perspectives. Over the hole sits a small round receptacle into which individual disks may be placed using the special disk forceps included in the kit. When the knurled knob is turned, the tiny fusee chain drives the disk rotation. This chain has a width of only about 1/3 of a mm.

In addition to rotating the disk, the orientation of the disk-holder can be changed in two additional ways. It can swing in an arc parallel to the stage, or the disk-holder mechanism can rotate in a sagittal plane, allowing the axis of rotation of the disk itself to be vertical, horizontal, or anywhere in between. There are two (of the original three) plates of disks with numbers from 25 to 48 on one plate and 49 to 72 on the other. One plate has four short black metal feet while the other has longer feet to allow it to stack on top of the other without disturbing the disks on the plate below. All pack into the original fitted mahogany case. In use the subjects are permanently or temporarily glued to the disks. Because of the long feet, the disks can be stored on the plates, without the plate stacked above disturbing the specimens. Each disk has a groove and the special forceps has a matching pattern to fit into the groove to hold each securely when placing it on, or removing it from, the device.

revolverrevolverThe image to the left illustrates how turning the knurled knob, rotates the disk 'd'. The tiny chain (best seen in the image to the right), travels through the black tubing supporting the disk rotating mechanism to act on the axis of the disk rotator.


The following images illustrate the movements of the device swiveling in an arc parallel to the stage:

 Microscope
Microscope
Microscope


The next set of images illustrate the movements of the device which changes the direction of the axis of rotation of the mechanism, so that when the chain is activated, the axis of rotation can be vertical, horizontal, or anywere in between.

 Microscope  Microscope
Microscope  Microscope
Microscope  Microscope



HISTORY OF THIS ACCESSORY

disk revolver

The 'Revolving Disk Rotator* for Opaque Objects' was first reported by Richard Beck in the Transactions of the Microscopical Society of London, New Series, Volume X, 1862. In the initial description, Beck described only one way to store the disks, namely on cylinders. The first catalog of Smith Beck and Beck, and also Beck's Treatise, both from 1865, show two different options for storing the disks. One was a cylinder (figure 4 A), with each hole numbered, which fit into a cylindrical brass case(figure 4 B), similar to the cans used for objectives; this version was offered from no later than 1865 but was no longer offered in 1888. Although they were the first form of storage, the cylindrical holders were less popular, and can be used to date examples to the nineteenth century circa 1862-1887. Although they were found in the 1882 catalog, by the 1888 catalog, the cylinders were no longer offered.

The other disk storage device consisted of brass plates with holes for each disk numbered(figure 8); it also featured little legs to allow these plates to be stacked on top of one another without crushing the specimens. The rotator was offered by Beck through at least the first decade or more of the twentieth century, as is illustrated by catalog entries. The plate storage for disks continued to be offered in the catalog as long as the disk-revolver was offered into the early twentieth century. Examples with these more common disk holders cannot be dated except to the broad range(c. 1865-1912), that I noted above.

Despite its production for half a century, the rotator is uncommon today, likely because it is unsigned and unless part of a microscope outfit, would likely be a mystery object to most people unfamiliar with it-even some collectors and microscopists. Another factor contributing to its rarity is that it was rather expensive in its day. The device came highly recommended by such authorities as Carpenter(1881), who found the device very useful for the study of Foraminfera. It would also be an ideal device to study something like a three dimensional crystal.

More sophisticated apparatus to allow rotation in multiple axes with calibrated scales were later developed for petrographic work and can be seen in Daniel Kile's 'The Petrographic Microscope: Evolution of a Mineralogical Research Instrument' which was a special issue of the Mineralogical Record, published in 2003 and is still available. You can see also see Dan Kile's article on multiaxis stages.


The author would like to acknowledge the help of his good friends, Dr Joseph Zeligs, and Jim Solliday, who, as usual, were kind enough to provide very useful historical and catalog information. Their insight and historical information has been critical to improving this web site.

*Strictly speaking the earlier term that Beck himself used, rotator, would refer to the rotation of the disk on its own axis. Revolution would refer to horizontal movement of the disk with the axis at the point where the apparatus attaches to the support plate, which although possible with the device, is a less unique part of its function as even a stage forceps has this motion.


The author is very grateful to Mr Tony Smith for providing the photographs seen here. This page would not be possible without his images.