Microscope of the Month
Upright, Amici Reflecting, and Lucernal Microscope Compendium by Carpenter (No. 37)
Age: c1830
Made by: Philip Carpenter
Made in: London, England
Lucernal configuration
Upright configuration
Imaging
This microscope system is a complete optical compendium consisting of an Amici reflecting microscope, an upright compound microscope, and a Lucernal microscope. All three configurations are supported by the same folding tripod base with its large single pillar. At the top of the pillar is a compass joint that is attached to that is a horizontal tube. The square stage/mirror assembly support pillar inserts into this tube. Bolted to the top of the tube are two support legs for the main microscope body. There are multiple objectives that can be screwed into this tube; seven have single biconvex lenses and are used in the upright configuration. There also are two low magnification lenses for use in the lucernal configuration, and one Amici reflecting objective. The compendium has three eyepieces: one for lucernal, one for upright and a third used only in the Amici configuration. As a lucernal microscope it can be configured with a large, low magnification eyepiece or, by removing a large lens and inserting a circular ground glass, can be used as a more typical lucernal instrument whereby both eyes can be used to examine the specimen. In the upright configuration the microscope is more conventional and can be used in transmitted light or reflected light mode. In the latter case either the two Lieberkuhn reflectors or the main mirror can be used to illuminate the sample by swinging it around to reflect down onto the sample.

The sample stage consists of two rectangular pieces and accommodates several different sample holders for dry and aquatic specimens. The top plate has rack teeth machined into two sides. The bottom piece has matching pinions with small, knurled knobs projecting down. This mechanism, or mechanical stage, allows for smooth X and Y movements of the sample. Focus for all configurations consists of a rack & pinion mechanism, with the rack machined into the descending stage/mirror support rod. This rod itself is inserted into a second, larger rod that telescopes into the tube just above the compass joint. Both rods can be extended for low magnification, long working distance objectives (mainly for Lucernal imaging). Imaging in all three configurations shows various degrees of chromatic and other optical aberrations.

When the user wished to convert the microscope to the Amici, or reflecting microscope configuration the stage/mirror rod could be removed and a circular clamp attached. This clamp would then be bolted to the nosepiece of the main microscope body. The result would be that the stage and mirror would be set at a right angle to the microscope body instead of axially as in the upright and lucernal configuration. The working distance of the Amici "objective" is very short, so a cylindrical spacer needed to be attached to the stage, thus moving the spring stage and sample much closer to the optical entrance.

An Amici microscope is essentially a reverse reflecting telescope. Light from the sample is reflected through a side port, off a small plane mirror, and onto the parabolic surface of a highly curved mirror. If the plane mirror is placed at the focal point of the mirror, image rays would be transmitted axially through the microscope body tube to a high magnification eyepiece (here engraved "Eyepiece for Reflector"). This type of microscope was invented by Amici to overcome chromatic aberration, but it fell out of favor due to the difficulty in polishing the extremely small parabolic mirror. Clay and Court (1932) describe a similar Amici instrument made by Cuthbert c1826. Giovanni Battista Amici (1786–1863) invented the reflecting microscope in Florence, Italy in 1813. His work led to the development of an aberration-free microscope that could obtain high magnification (up to 1000x). Only a few manufacturers including Amici succeeded in creating reflecting microscopes including Cuthbert, Charles Chevalier, and Carpenter.

The system is stored in a large mahogany case, and contains a complete set of accessories, optics and mechanics. Additionally, there is a hand-written pamphlet describing assembly and use of the equipment, plus a printed advertisement of the instrument from a journal. The pamphlet is signed "Carpenter". One leg of the instrument is engraved "Carpenter. 24 Regent St., London". Height 50cm.

Philip Carpenter (1776–1833) had a shop making optical instruments at 111 New Street Birmingham where he first started making reflecting microscopes. In 1826 he moved his shop, "The Microcosm", to 24 Regent Street, London. From this location he sold optical and other scientific instruments such as compasses, telescopes, and microscopes. After his death his sister Mary along with a former apprentice William Westley continued to run the business renaming the firm Carpenter & Westley in 1835.

This instrument was featured 07/2015 with considerable help from Ms. Riley Maxon.

Contact: Steven Ruzin, Ph.D. Director of the CNR Biological Imaging Facility
and
Curator of The Golub Collection
located in
Valley Life Sciences Building, Onderdonk Lobby
The University of California at Berkeley, USA
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