Spencer Lens Co. #7CBH, 1925

What equipment do you use? Post pictures and descriptions of your microscope(s) here!
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apochronaut
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Spencer Lens Co. #7CBH, 1925

#1 Post by apochronaut » Thu Jun 04, 2015 3:57 pm

This microscope was , along with the # 14 , Spencer's premier research instrument during the 1920's. It morphed into a chrome plated version with an optional inclined binocular before it was replaced by the # 5 in the early 30's.
There were several features of microscopes that experienced microscopists clung to ,due to tradition and familiarity, during the production of this microscope. The #14 was identical to the pictured scope except that the fine focus control was in the traditional central place above the arm. The # 7 was a modern departure from this , with the 1 micron graduated fine focus 1 inch knobs on the sides, proximal to the coarse focusing knobs. Each came with various stages. The pictured stage is a circular revolving stage, with coaxial xy controls, 360 degree rotation graduated in degrees, and a pair of orbital controls at 90 degree angles to each other on either side of the arm. Later , Spencer expanded their offerings of circular revolving stages to 4 models, with the xy controls of various designs. This one became catalogued by 1945 as the V stage. A triple nosepiece was the maximum possible but the early 30's a quadruple was also offered. Objectives could be either achromat, fluorite or apochromat. This particular instrument is currently fitted with a 16mm 10X .25 achromat, a 4mm 44X .70 achromat and a 2mm 82X 1.30 apochromat. The 2mm apochromat for most of the almost 60 years of it's production was usually a 90X. The lower magnification version, such as this one is, is uncommon and was only catalogued briefly. Spencer catalogued a wide array of compensating oculars( 1.5x to 30x) but did not catalogue a 12x until sometime later, so a calculation of 82x( later bumped to 85x) X the 15x fitted in this scope gives 1230 diameters or pretty close to the theoretical limit one would expect with the N.A. 1.30 achromatic condenser, supplied.
The substage is centerable, and has a separate crescent diaphragm below the main iris, controlled by the knurled knob below the filter slot. There is also a condenser fine focus controlled by the little brass knob on the right side, with the coarse focus on the left.The plano/convex mirror is focusable by sliding it up and down a rail. Unusual for it's time(cat. in ) the condenser mount is a slip in and slip out dovetail, held in place by two spring loaded buttons located at about 3:30 and 8:30.It is an almost faultless design that has become the standard condenser mounting system, on most modern microscopes.
Oh, yes ... the other traditionalist feature. As an option you could order the combination binocular monocular body.The last picture shows the body shifted over into the monocular mode by unlocking with the little bowling pin shaped locking lever on the back of the prism housing and shifting it over. There are also hinged doors that could be flipped up to block either the right or left eye. They went to great lengths to attract the old guard monocular users and of course, hopefully convert them . By 1932 or so the combination body was not catalogued.
Photomicrography was accomplished by fitting a dedicated camera lens into an extra large monocular tube, which could be rapidly interchanged with the visual body by releasing a dovetail fitting on the front of the microscope, leaving everything else behind but the binocular body. The bodies could be interchanged in a matter of seconds and a picture be captured with the prefocused camera tube.
It is a surprisingly easy and comfortable microscope to use and yields very fine images. Spencer offered 9 illuminators during this period , from the ubiquitous 15 watt understage illuminator we all know, to a 400 watt Mazda lamp with 4 inch collector lenses. The model 370 100 watt illuminator is what I normally use. It has a 100 watt bulb with a 3 inch collector and 3 inch field diaphragm, so perfect kohler illumination is at hand, and it's mounting rail allows it to be used for above stage incident illumination, as well.
Attachments
Upper right corner: release knob for the body tube dovetail.<br />Lower right: locking lever for body tube slider.<br />Upper left: lever for left hinged shutter.
Upper right corner: release knob for the body tube dovetail.
Lower right: locking lever for body tube slider.
Upper left: lever for left hinged shutter.
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1.3 N.A. achromatic condenser and substage.
1.3 N.A. achromatic condenser and substage.
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Interpupillary distance adjustment on the left, diopter adjustment on the right and 15x compens oculars.
Interpupillary distance adjustment on the left, diopter adjustment on the right and 15x compens oculars.
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Closeup of the circular rotating mechanical stage.
Closeup of the circular rotating mechanical stage.
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Spencer # 7CBH microscope
Spencer # 7CBH microscope
DSC00552 (1280x719) (575x1024).jpg (148.67 KiB) Viewed 6423 times

apochronaut
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Re: Spencer Lens Co. #7CBH, 1925

#2 Post by apochronaut » Thu Jun 04, 2015 4:06 pm

One more picture.
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The microscope adjusted for monocular use.<br /> It does occur to me that with modern digital cameras, a dedicatedcamera could be attached to the other ocular tube and be moved over , quickly for a picture, if one didn't mind using a monocular microscope.
The microscope adjusted for monocular use.
It does occur to me that with modern digital cameras, a dedicatedcamera could be attached to the other ocular tube and be moved over , quickly for a picture, if one didn't mind using a monocular microscope.
DSC00558 (1280x719) (574x1024).jpg (120.36 KiB) Viewed 6422 times

Dennis
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Re: Spencer Lens Co. #7CBH, 1925

#3 Post by Dennis » Thu Jun 04, 2015 4:38 pm

Please excuse my ignorance but what would it be- a Stereoscope? I am just seeing you raise and lower the tube and not the stage.
Or are a lot of earlier microscopes this way and I never noticed?

-Dennis

billbillt
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Re: Spencer Lens Co. #7CBH, 1925

#4 Post by billbillt » Thu Jun 04, 2015 4:44 pm

It appears to be a type of Petrographic Microscope to me... And a very well made one!...

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gekko
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Re: Spencer Lens Co. #7CBH, 1925

#5 Post by gekko » Thu Jun 04, 2015 5:12 pm

Wonderful instrument and superb, detailed description of structure and function, as well as excellent images. I enjoyed the post. Thank you, aphochronaut!

apochronaut
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Re: Spencer Lens Co. #7CBH, 1925

#6 Post by apochronaut » Thu Jun 04, 2015 6:37 pm

billbillt wrote:It appears to be a type of Petrographic Microscope to me... And a very well made one!...
No, the objectives are corrected for .17 coverslips. This is a biological microscope. You could purchase a plain square stage, with spring clips, a square mechanical stage with separate x and y controls, a square stage with coaxial xy controls, a slightly less sophisticated round stage and this research circular rotating stage. This was the biological research stand par excellence in the early 20's. If you look more closely at the stage ,it has a fairly standard slide holder with a claw to grip the slide. Spencer had a feature going way back of floating the slide. It is gripped in a little pair of bevels, which elevates the slide just above the stage, so it doesn't drag on the stage when moved.
Spencer also made contemporary to this microscope what were then called " Chemical microscopes". The objectives were not cover slip corrected and were strain free for polarizing work. There was also a circular mechanical stage built for those but due to the sometimes large nature of the object, the controls were placed to the rear of the stage and were ambidextrous; two on each side, allowing for a fairly large flat surface for industrial materials analysis.
Later they produced a whole range of polarizing microscopes, then industrial metalographs. Generally these were catalogued separately and included a whole scad of polarizing accessories.
For, Dennis. This microscope has the focusing optical tube, much as almost all earlier microscopes had. If you look at your Bausch & Lomb, it uses the same rack and pinion system on a fixed optical tube.
When reversed microscopes came to be commonplace, the low positioning of the focusing controls to some degree dictated the choice of using a focusing stage. Spencer/AO alone, continued the focusing nosepiece design right until the end of production, even with large reversed stands. The benefits of the focusing nosepiece are; the stage stays at the same height at all times, for more ergonomic operation and the nosepiece is cushion mounted, so the objectives need not be. This is allowable due to the infinity corrected optics employed in the AO nosepiece only focusing system.
I forgot one detail about it and subsequent Spencer research stands. With the exception of the shroud that covers the prism body, the entire microscope is brass, then nickel plated, brass plated on brass, or enameled. Spencer continued this with their research stands until about 1956, when they discontinued the # 5 research stand at the introduction of the series # 4 Apostar, which was largely cast iron and cast aluminum. The microscope weighs 17 lbs.

billbillt
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Re: Spencer Lens Co. #7CBH, 1925

#7 Post by billbillt » Thu Jun 04, 2015 7:22 pm

It is still a wonderful instrument!!....

Charles
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Re: Spencer Lens Co. #7CBH, 1925

#8 Post by Charles » Thu Jun 04, 2015 10:38 pm

That's a purdy Spencer. Love the brass and black era.

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Crater Eddie
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Re: Spencer Lens Co. #7CBH, 1925

#9 Post by Crater Eddie » Fri Jun 05, 2015 1:17 am

Beautiful!
Olympus BH-2 / BHTU
LOMO BIOLAM L-2-2
LOMO POLAM L-213 / BIOLAM L-211 hybrid
LOMO Multiscope (Biolam)
Cameras: Canon T3i, Olympus E-P1 MFT, Amscope 3mp USB

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