Through the microscope

Archive for the ‘Microscopy – all posts’ Category

Spencer juggy rescue

I bought this Spencer jug-handled microscope some time ago, at first glance it doesn’t look too terrible, a broken mirror holder and a missing mirror; but if you look again you will see that the poor thing has been spray painted black from top to bottom. The objectives, the coarse and fine focus knobs – everything is painted. This is a serious rescue, I have never had to use paint stripper on a microscope before but this calls for desperate measures. As you can see in the last picture, so far not too terrible, there is hope. I have stripped the black paint off the focus knobs, and underneath the paint the coarse focus has polished up pretty well. I have to de-corrode the other parts and see if I can get a polish on them good enough for hot lacquering. It’s not so much a restoration as a salvage operation, but I have a soft spot for jug handled microscopes Wish me luck.

Image

Stentor

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Blepharisma

Just a quick post of some blepharisma taken using Gladys, the Zeiss Universal microscope. Blepharisma are naturally pink coloured, no stains have been used. They are also very speedy, I did not narcotize these little chaps so I had to use a fast shutter speed. The pictures with the grey background were taken using phase contrast.

bleph 24bleph 20bleph 18bleph 13bleph 9bleph 7bleph 5bleph 1

 

 

 

Microscope World Blog: Tongue Taste Buds under the Microscope

Info on tongue taste buds in humans and animals and images captured under the microscope at 40x, 100x and 400x magnification.

Source: Microscope World Blog: Tongue Taste Buds under the Microscope

Dark ground at high magnification

Dark field, or dark ground microscopy give very pleasing images, specimens appear white on a black background. It is easily achieved at low magnification by popping a patch stop (a clear filter with a central black circle) into the filter tray under the substage condenser.They are simple to make, you just have to make some filters with central stops of different sizes to determine which size stop works best for you.

patchstops

patch stops of different sizes

Explanations of dark ground are a google search away but basically a patch stop blocks the central portion of light leaving a circle of light around it. This allows light that has been scattered by the specimen to be viewed whilst removing zero order light. This produces the bright, beautiful dark ground images with which we are familiar.

monochromatic-light-diffraction-grating-nov2010p21q5

zero order light

At low magnification it is easy, pop in a patch stop and away you go. At high magnification it is much trickier. At higher magnification you need a proper dark ground condenser that can be used with oil and you must also reduce the numerical aperture of the objective using an iris objective or a funnel stop.

The other problem is that is quite hard to centre  a condenser when there is very little light coming through. I find it best to set up in bright field and then switch condenser tops so I know that I am centred.

Below are some pictures of Pleurosigma angulatum and some other test diatoms taken on a Vickers M4000 with a 100X oil objective and a dark ground condenser.

 

My favourite slides

Tell Tale Tit,
Your tongue shall be slit;
And all the dogs in the town
Shall have a little bit.

I don’t just enjoy microscopes, I’m also very interested in certain types of slides, I have quite a collection of tongue slides. Why tongues? I really have no idea, I think it is because my father’s dissertation was on cat tongue. For many years our cupboards at home were filled with slides of cat tongue. Nobody ever looked at them, they just sat there in boxes. When my father died the slides were thrown away; he was an excellent histopathologist but I had studied plants so never looked at the slides of cat tongue..

It was a few years after my father’s death that I started to become interested in microscopy, I had a microscope I bought as a student but no slides so I bought one on eBay – a slide of cat tongue. Later, I saw rabbit tongue on eBay, then rat, and so it went on. I don’t have a vast collection but tongue slides are the only slides I can get quite silly about.

The parrot is particularly interesting, I can only imagine from the lack of taste buds that they have very little sense of taste. Otter looks like it’s a cross between dog and cat, and I always think that dog tongue looks like bacon. It probably tastes like bacon too, not that I’m suggesting you try it… but tongue is a muscle and on the whole muscles taste good. I’m sure people would be less keen on rump steak if it was called cow’s butt.

Here’s a selection of my tongue slides:

Video

Displacement reaction under the microscope

The first video shows what happens when copper wire and silver nitrate are allowed to react under the microscope. The video was recorded using Gladys, the Zeiss universal with transmitted light. Because the silver formed is not transparent it appears in silhouette. The pink background was achieved using a rheinberg filter.

The second video shows the same reaction viewed under a stereomicroscope using incident light. The magnification is not as great using the stereomicroscope but it is fun to see how the different types of microscope give a different perspective on the same reaction.

Gallery

Crystals under polarized light

Some pictures I have taken recently using Gladys the Zeiss Universal microscope. These pictures are at 63X as I remember. Salicine (aspirin), safranin O (a stain having the formula C20H19ClN4) and Platinocyanide of magnesium, the latter is an antique one with an antique name. Nowadays it would be called magnesium platinocyanide.

Slides of crystals are very easy to make either by melting the compound onto the slide or allowing a solution to crystallise onto the slide. One day I’ll catch a snowflake…

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A restored brass microscope

This is the piece I have practiced and learned lacquering on. I hope you agree it is a dramatic improvement!

It is a Dunscombe microscope. Dunscombe was the son-in-law of Braham and took over his father-in-law’s optical business. In fact, there is still a Dunscombe Optician’s in Bristol UK where they lived and worked.

This microscope has been stripped, cleaned, polished, straight grained and lacquered about 20 times over the last couple of years while I have practiced the art. I have to admit that I intend to strip it again because there are a couple of pieces that are not quite up to my exacting standards. For now it will stay as it is. I have other microscopes to work on and I have had enough of this particular microscope for a while.

 

A new screw was made for the top to replace the nasty steel wood screw that had been shoved in there and two new screws were made to hold the microscope onto the foot. A new rack was cut on the milling machine and a new pinion was also made as the original rack and pinion were badly damaged and unusable. The stage was chemically blackened using a commercially available selenious acid based product. Not too shoddy I think.

dunscombe new pinion

New pinion (right) to replace original worn pinion

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Dunscombe of Bristol

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