T. H. McALLISTER NYC ANTIQUE BRASS FUSEE CHAIN DRIVE STUDENTS MICROSCOPE C-1880
McALLISTER NYC ANTIQUE BRASS FUSEE CHAIN DRIVE STUDENTS MICROSCOPE C-1880. McALLISTER OF NYC ANTIQUE BRASS FUSEE CHAIN DRIVE STUDENTS MICROSCOPE CIRCA 1880.
McAllister, Manufacturing Optician, New York, NY in circa 1880. This instrument is signed on the upper front face of the body tube, T. (Please see the accompanying close-up image that shows this inscription). This is a very fine example of his Student Model Microscope that features his version of the fusee chain drive system for coarse focus rather than the more conventional rack and pinion focus system found on the majority of the microscopes produced during the latter part of the 19th Century. It also features an uncommon tilting stage fine focus system in lieu of other more popular types of fine focus mechanisms used on most microscopes from this same time period.
Accompanying this listing is a catalogue cut of McAllisters Students Microscope Model as extracted from my personal copy of his January 1880 Microscope Catalogue entitled, Illustrated Price List of Microscopes, Microscopic Apparatus, Lenses, Etc. 49 Nassau Street, New York, Thirty Seventh Edition. The exact similarities to the featured instrument are readily apparent.
This microscope lacks a standard serial number. It appears that McAllister did not serialize most of his microscopes, so obtaining an exact date of manufacture of this instrument is not possible.However, based mainly on its overall design derived from catalogue descriptions, it appears to date from circa 1880. This fine instrument with its unusual fusee chain drive coarse focus system and its uncommon tilting stage fine focus mechanism will make a very nice addition to any antique microscope collection, especially one that has a focus on American made instruments.
This instrument is built upon a simple Y shaped foot (yellowgold brass painted metal) with integral dual flat pillars or trunnion plates that rise to a trunnion joint. A trunnion bar between the pillars supports the stage and the rest of the microscope. The trunnion joint allows the microscope to be tilted to any angle from the vertical for the comfortable viewing of specimen slides.
The trunnion bar, lower plate of the dual part stage and limb of this microscope are one integrated piece of cast brass. This instrument is equipped with an 85mm long by 70mm wide rectangular stage with a 15mm central aperture. A pair of slide clips is found atop the stage.The stage consists of a lower fixed brass plate along with an upper moveable brass plate that is hinged on the left side, but free to move up or down in the vertical direction by engaging or relaxing a brass milled head attached to a screw found on the right underside of the stage. This screw penetrates the lower plate in a threaded borehole and engages with the upper plate thereby tilting the upper brass plate slightly.
This relatively uncommon arrangement allows the stage to provide a form of fine focus that is relatively precise given the magnifications available to this instrument. Screwed into the center of the lower stage place is a brass cylinder.
A rotating disc of apertures is slip-fit into the brass cylinder. Also under the stage and affixed to a brass bar extending from the center of the leading edge of the trunnion bar is a yoke mounted 40mm diameter plano-concave mirror mounted in brass. The mirror bar can be moved to the right or left to provide either direct or incident illumination to the stage above. Also, the mirror itself and be moved up or down on the mirror bar either closer to or away from the underside of the stage. Rising from the rear of the stage is a curved limb that terminates in a vertical straight section. Housed within this latter section is a unique fusee chain drive system that provides for coarse focus of the body tube in lieu of the more standard rack and pinion coarse focus systems found on most microscopes of the time. The fusee chain coarse focus drive system was first invented in the UK by William Ladd and is employed by McAllister on this microscope model and on all his large microscopes. McAllister described his version of the fusee chain drive in his catalogues variously as a chronometer chain movement or as, a delicate watch chain movement. Accompanying this listing is a series of images that will help you to understand how this fusee chain coarse focus system is designed and how it works. IMAGE A shows how the fusee chain device consisting of a flat rectangular brass bar is attached to the upper end of the body tube with a single screw (body tube removed from the microscope stand for clarity). This screw holds the device to the flat dovetail on the back of the body tube, but is relaxed enough to allow the rectangular brass bar to move slightly up or down along the outer face of the dovetail attached to the body tube. The fusee chain itself is anchored into the distal end of the flat rectangular brass support bar. At the upper end, there is an open brass box section that fits over a fixed U-shaped post on the body tube dovetail. In the center of the brass box is a vertical threaded rod anchored on both ends of the box with an adjustment wheel attached that is able to move over the threaded rod. When the adjustment wheel is moved, it impacts the U-shaped post thereby moving the entire rectangular brass bar with the attached fusee chain either up or down.Thus, it serves as a tension adjuster for the fusee chain. IMAGE B shows how the fusee chain is wrapped around the spindle of the coarse focus system equipped with dual milled heads on either side of the limb. Note: The image shows 3 wraps of the chain.
However, in practice, I found that only one complete wrap of the chain was needed to work the focus based on the total length of the fusee chain provided with the instrument. IMAGE C shows how the distal end of the fusee chain is anchored to the lower end of the body tube dovetail by a brass screw. The lower end of the chain is held in place under the screw head with a 4mm jump ring that attaches to an open port on the end of the fusee chain.
IMAGE D shows the fully assembled system on the microscope. The top end of the limb is split to allow a screw threaded through the limb to adjust the tension of the receptacle that accepts the dovetail of the body tube. Another similar tension adjuster screw is found at the base of the limb under the right coarse focus milled head. Both of these screws allow for fine tuning of the dovetail tension. By carefully adjusting the fusee chain tension wheel along with the two (2) screws on the right side of the limb that control the dovetail tension of the body tube, one is able to obtain a suitable mechanical equilibrium that affords a relatively sensitive and exact form of coarse focus using this unique fusee chain drive system. The lacquered brass body tube of this microscope is equipped with a relatively long brass drawtube with a single position marker inscribed into the approximate mid-point of the tube.The distal end of the body tube is equipped with an unmarked low power objective lens with RMS threads. When this instrument is set up for observations with the body tube and the drawtube fully extended, this microscope stands about 17.5 inches tall. Note: Please see the accompanying image that compares the height of the microscope to a standard size wine bottle. When the body tube is racked down to its lowest level and the extension tube is fully nested within the body tube, the microscope stands about 12.5 inches tall.
The microscope weighs about 5 pounds. There is no wood case or any other accessories that accompany this instrument.
NOTE: The accompanying images, which were captured under ambient light conditions, are considered to be a part of this statement of conditions. Please take the time to view all of the images so you will be able to confirm the condition of the microscope and so you will know in advance what you will be getting should you prove to be the fortunate new owner of this American made antique brass microscope. Overall, the condition of this microscope is deemed to be good to very good. The painted metal parts of the microscope have some dark spots, paint cracks, scratches and dings from use, which are to be expected for a microscope of this vintage (now some 140 years old and counting). The brass lacquered parts of this microscope are in fair to good condition with just some surficial tarnish evident consistent with the age of the instrument. I would estimate original lacquer retention on the lacquered brass parts to be in the range of 92 to 96 %. The only treatment we have given this instrument was to clean it of dust and grime with dilute Windex and then to give it a coating of Renaissance Wax from the GEMMARY to preserve the original lacquer.NOTE: WE GENERALLY MAKE IT A PRACTICE NOT TO DEEP CLEAN AND POLISH ANTIQUE BRASS MICROSCOPES. HOWEVER, ON OCCASION WE MAY DO A PARTIAL OR COMPLETE INSTRUMENT RESTORATION BASED ON THE OVERALL COSMETIC CONDITION OF THE INSTRUMENT UPON RECEIPT. Optically, the eyepiece is in good condition with no significant internal defects evident.
However, as noted above, the eyecup is missing from this ocular. Similarly, the objective lens is in very good optical condition. The eyepiece and objective in combination produce well resolved images of prepared specimen slides when viewed with this instrument. The plano-concave mirror is in excellent condition and provides very good illumination to the stage.Mechanically, the fusee chain coarse focus system works smoothly, but its adjustment is a bit touchy. Some care is needed to adjust it properly and special care needs to be exercised not to over tension the fusee chain to the point where it may break.
It is of interest that the fusee chain on this microscope is 100% intact and fully functional. Many microscopes equipped with this type of focus system are often found with the fusee chain missing or broken. Fortunately, this instrument has an intact fully functional fusee chain.
The rotating disc of apertures rotates freely. The tilting stage fine focus mechanism works perfectly. All in all, this is a nicely preserved example of T.
McAllisters Students Model Microscope that is certainly worthy of any antique microscope collection. Here is your opportunity to own a relatively rare example of an early American-made brass microscope with a unique fusee chain drive coarse focus system and tilting stage fine focus system for your collection. McALLISTER & THE McALLISTER DYNASTY OF OPTICIANS. His business was first established on Market Street in Philadelphia. Around the year 1783, he decided that spectacles might be an appropriate addition to these other wares and so the first American optical shop in America was born.
McAllister thus began a dynasty of opticians and optometrists that continued on into the early years of the 20th Century and lasted some 5 generations. He is now recognized as the Father of optometry and opticians in the USA. McAllister, the oldest son of John McAllister, Sr. Established his own optical business in the year 1783 at 48 Chestnut Street, Philadelphia.He ultimately became a wholesale supplier of telescopes, microscopes, barometers, thermometers, hydrometers, as well as a host of other scientific instruments and scientific glassware. Many of the instruments were imported from Europe. Queen joined him in the year 1852 and became a partner in 1853 operating under the trade name, Queen and McAllister. This partnership was dissolved in 1854, when Williams younger brother, John McAllister took over operations of the firm.
Queen subsequently started his own business in Philadelphia in 1854, which became James W. Queen and Company in 1860.
The McAllister brothers continued operations in Philadelphia to the year 1865 under the trade name of McAllister & Bros. After the year 1865, it appears that John McAllister retired from the business, leaving his older brother William Y McAllister as the sole proprietor of the firm. In May of 1867, William Y. McAllister issued a trade catalogue entitled, Catalogue of Optical & Philosophical Instruments, For Sale Wholesale and Retail. At this time the business was located at 728 Chestnut Street, Philadelphia.
McAllister did not make microscopes, but imported several lines from Europe. In the meantime, yet another McAllister brother, Thomas H. He operated under the trade name McAllister, Manufacturing Optician. His first commercial product was his Compound Household Microscope, which was introduced in the year 1867 making him one of Americas first microscope makers. This was a relatively small, economically priced microscope aimed at schools and families.This little microscope was ultimately praised in the educational journals of the day for helping schools with low cost instruments for students. McAllister did not make his own objective lenses. He described them in his catalogues as good achromatic French objectives. He also made (or possibly imported for resale under his name) paper covered slides for distribution with his microscopes, especially with the Household Microscope.
McAllisters catalogs/price lists published in the 1870s describe several larger instruments including his Students Model Microscope, The Popular Microscope, The Professional Microscope, and The Physicians Microscope. All of his larger microscopes employed a fusee chain driven coarse focus system first introduced in England by William Ladd and later also used by Smith, Beck and Beck on their Universal Microscope. In his catalogues, McAllister described his version of the fusee chain drive as a chronometer chain movement. McAllisters microscopes were made into the early 1890s. By the turn of the century, the primary focus of the firm had turned from microscopes to the manufacture of Magic Lanterns and Lantern Slides.THE MONTANA LOGGER is very pleased to offer this antique brass Students Microscope by the American Optician, T. We will also entertain reasonable offers for this microscope that has some very unique features that will be of interest to astute collectors. FREE scheduling, supersized images and templates.
Make your listings stand out with FREE Vendio custom templates! Over 100,000,000 served. Get FREE counters from Vendio today! McALLISTER NYC ANTIQUE BRASS FUSEE CHAIN DRIVE STUDENTS MICROSCOPE C-1880" is in sale since Wednesday, October 28, 2020. This item is in the category "Collectibles\Science & Medicine (1930-Now)\Scientific Instruments\Microscopes, Lab Equipment".
The seller is "mtloggera" and is located in Hamilton, Montana. This item can be shipped worldwide.
McAllister