Saturday, March 4, 2017

Magnification table and butterfly wing scale dimensions

As far as I can tell Bausch & Lomb didn't include a magnification table inside the lid of their microscope cases. This was common practice for most European makers. Sometimes filled out by hand for the objectives and eyepieces included with the instrument, sometimes it was a table of the full range with the included pieces underscored or circled.

What B&L did include with their instruments was the booklet on the use and care of the microscope. And on page 31 of the '37 printing is included a magnification table for their entire range.


Here reproduced to be able to print and rectify this small oversight of Bausch & Lomb. For reference (if you happen to have a B&L biological microscope), though multiplying the two values is not too hard of course.

What can be handy is to know the working distance - the 10 and the 43 objectives with distances to the object of 7.0 and .06 mm are confocal (or near enough). The 4 objective with a working distance of 38 mm clearly could not be mounted to be confocal. (An Olympus 4 times objective actually is just about confocal with the other B&L objectives, incidentally.)

One other number that can be handy to pencil in on this table is the diameter of the viewed image. To determine this, a calibration slide was sourced. From local, reputable dealers in matters microscopical these are startlingly expensive. However from the global 'dime-store' that is the internet, these can be had at very affordable prices including shipping half-way around the globe. These do not include a calibration report and certificates of course. As such these cheap 'calibration slides' are probably unacceptable for proper laboratory use, but excellent for the hobbyist.

Viewing the linear scale of the calibration slide using the 10 x eyepiece and successively with the 4, 10 and 43 objective yields the diameter of the image viewed at about 4.3 mm, 1.6 mm and 0.4 mm.


Looking at the scales of a butterfly wing, then for example the size of the individual scales can be estimated. The below image was taken with the 430x magnification, thus the diameter of the image is around 400 micron. The width of the scale in the centre of the image is thus about 76 micron.


Zooming in further on the digital image shows the ridge-pattern of the individual scale. Also very clearly evident is the very small depth of focus at this magnification. Note that viewing whilst fiddling with the fine-adjustment gives a much better impression of the object being viewed than a static digital capture.


These individual ribs on the centre scale can be counted (about 49), making these ridges approximately 1.6 micron apart. That is quite impressive and close to the maximum achievable for a light microscope.

And that for an 80 year old instrument too.   :-)

Friday, January 20, 2017

Principal Operating Parts of the Remington Noiseless Portable typewriter

Have had a Remington Noiseless Portable typewriter for a while now. Given the age of such machines when acquired second-hand, not surprising this came without its user manual. Recently just happened to spot the right instruction leaflet on a well-known global auction site. Surprisingly (or not) nobody else spotted or wanted it, so here is the machine with an original user manual.


This is a single sheet. Opening up the leaflet a cut-corner and arrow on the page underneath make it clear to the reader that there's another page to open. (That explains the arrow on my leaflet for the Victor T; that also has the arrow, but lacked the cut-corner.)


Side-by-side all the principal operating parts of the typewriter are identified and given a brief explanation in the list below.


On the back of the leaflet of course some advertising for Remtico ribbons and special Noiseless carbon paper. Nicely put are paragraphs on things to do and on things not to do.


The leaflet when folded is 8" x 5½", from a single 16" by 11" sheet printed on both sides. Will be making a reproduction copy for keeping with the typewriter. Already below scans of both sides in fairly decent resolution.

  

Now what would be the chances of some Remtico Noiseless carbon paper turning up online...

:-)

Monday, January 9, 2017

Moteur à ressort



An instruction leaflet for the Meccano motor number 2 (reversing). The address in Paris was the French factory at that time. This grand building still stands, currently a school.

This sheet must've been supplied in the late twenties' with a dark-red clockwork number 2 motor that was also in the lot. The motor itself was at least as ravaged by time as this cheap-paper sheet. Rusty and without its spring - if only they'd stuck to the instructions as supplied :-)
(Supplying these instructions in French and Italian may not have helped...)


This is a clockwork motor built into a model. Painted dark blue, it is a slightly later specimen. Apart from its late thirties' colour-scheme it is identical to the motor the instructions were for. One other difference with that dark-red motor in the lot is of course that this one is still working fine.

The motor is used here as the basis of a farm tractor, from the 1930 book of new models.


The black and white illustration in the book really doesn't do it justice - lots of shiny brassware!

Friday, January 6, 2017

Spanning almost a century with spoked wheels

Loosely based on a model in the instruction manual, a small motorcar built from early nickel parts.


Ribbon added by the kids; it's quite robust to be played with too. Survives rollovers just fine. Probably just like the real motorcar of around 1920, just keep a screwdriver handy to fasten any bits that become loose or rattle.

This was a first using of a recently acquired set of spoked wheels (19a). These are marked 'fabriqué en Angleterre' as early twenties' parts and were in 'used' condition. Some careful bending, cyanoacrylate for loose bosses and India ink to make rusty-patches less glaring; again good to go for building.


The small wheels for headlamps are more recent, but the double-bent bracket with the rounded corners supposedly was made not later than '16. Amazing how well these parts can survive.


The flanged plates too are probably a century old. They've got the 1913 patent marking, but no Meccano stamping yet anywhere.


The bush wheels are also twenties' articles, with the 'fabriqué en Angleterre' marking.


Impressive how well all these bits have weathered a century - and can still be toyed with and played with too :-)

Wednesday, January 4, 2017

Oy oy oy Jozsi

Shellac record...


Little surprise in a stack. A very 'chipper' record in a small stack of shellac records on the Imperial label. In an old box were about 15 records dating from around '32 from the German 'Imperial' company. Mostly popular songs from movies played by uncredited dance orchestras.

And this little gem.


:-)

Friday, December 30, 2016

Beige machine spotted

A beige and angular typewriter; Torpedo 'Cicero' in a shop.



Looked a bit dejected, three keys down.

To avoid any confusion, a small label explains that it is 'decoration' and not for sale. Either way, it is in a bit of a surprising spot. Placed in the cooking section next to the cutting boards. To be fair, also with cooking books. And it is a ''Chickpea' of course :)

Friday, December 16, 2016

Bausch & Lomb 32mm 4x objective

The newly acquired microscope came with two objectives on a three-position nosepiece. One empty spot to fill - ideally with a low power objective. The 10x objective is of the divisible kind, the lower portion can be unscrewed to change from a 10x to a 4x objective. (Snippet from the December 1939 issue of Popular Science.)


Even nicer would be to fit a 4x objective at the empty position. With the amazing global flea-market that is the internet, one such objective was found to be for sale. Even though it was located in Santa Barbara it was easily purchased and shipped with amazing speed to the Low Countries.


For being nearly 90 years old by now this objective is in fair shape, only one small blemish (nick) on the front lens. Whilst this will reduce sharpness in a part of the image, it is not in focus so not too damaging. This would probably make the objective be rejected for laboratory work, but for hobby-microscopy at low powers it is still fine.


To clean the objective, used demineralised water with a soft cloth. A 'camel-hair brush' to flick off larger dust or particles. When carefully wiping clean lens surfaces of 'condensed' dirt, regular tap water would evaporate and leave a thin film deposit on the lens. With demineralised water, it can be gently (!) wiped clean and dry.


With three objectives of the right pattern fitted in the nose-piece, it does look the part again. Also it now works fine for magnifications from 20x up to 430x. For practical, hobby use, that's plenty of power.