Early Photographs of Test Diatoms

[desertrat]

Ran across this while doing some web surfing. The paper is about using scanning electron microscopy to measure differences between individual specimens of test diatoms. It also includes some very old historical photographs of some of these diatoms, along with a history of the practice of using diatoms to measure the performance of objectives.

A sample entry:

The striae of Amphipleura pellucida were first resolved in 1869 with a Powell & Lealand 1/16" water immersion objective.

http://www.microscopist.co.uk/wp-conten ... -paper.pdf

[75RR]

Thanks for the link

Particularly impressed with the Pleurosigma angulatum photographed on the 23 of December 1878!

That is 140 years ago - great effort for the time. Holds up well even today!

[MichaelG.]

A great 'benchmark' reference ... Thanks for sharing it.

MichaelG.

[MicroBob]

Hi together,
here is a link to a photo of Amphipleura pellucida made by van Heurck in 1891:
http://www.baertierchen.de/feb2004.html

I have tried myself to resolve the detail in this diatom and it was really difficult.
I ended up with a heavily decentred cadioid condenser and then was able to resolve the pores with a humble 100:1 n.a. 1,25 Zeiss achromat.
The oldtimers had one advantage: they used the yellow arsenic based medium with refractive index 2,3 or so. This gave them lots of contrast, especially in a very fine diatom like Amphipleura pellucida.

The success on this diatom in 1869 is really quite incredible. Immersion objectives were just invented and water immersion is not as good as oil immersion. This was only 30 years after the achromatic objective was invented and they started to see more than Leeuwenhoek did another 180 years before!

Bob

[desertrat]

Hi Bob,

Interesting coincidence. I was looking up information on Van Heurck earlier today, and Google brought up an English version of the website you linked to:

http://www.baertierchen.de/wb_feb04.html

I also found and downloaded the 1891 edition of The Microscope and Its Revelations at the Internet Archive, almost 1200 pages and over 100 megabyte file size. It goes into more detail about the Van Heurck A. Pellucida photograph and the Zeiss optics he used, and was referenced at the above website.

Unfortunately, my browser, which has a .pdf reader extension, crashed from the huge file size before I could locate the plate with the photographs.

https://ia800400.us.archive.org/32/item ... carp_1.pdf

[MichaelG.]

Unfortunately, my browser, which has a .pdf reader extension, crashed from the huge file size before I could locate the plate with the photographs.

Allow me:

Plate XI

IMG_2500.jpg (229.67 KiB) Viewed 10208 times

MichaelG.

[ImperatorRex]

Thanks Michael,
some details:

Recordings by van Heurck with monobromnaphthalene immersion.

The first three figures represent the Amphipleura pellucida Kütz. Fig. 3 shows the resolution in lines at 2000x magnification (in the original). The beads can be seen in Figures 2 and 1 at magnifications of 2000 and 3000x, respectively.

Fig. 4: Fragment of a shell of Amphipleura Lindheimeri Grun. This species is different from Amphipleura pellucida Kütz. only by their proportions, being much larger and their stripes coarser. The beads or openings in the lattice appear as squares. Magnification 2500x.

Fig. 5: Pleurosigma angulatum W. Sm. Accurately adjusted to the hexagonal openings in the latticework. About 10,000 times.

Fig. 6: Pleurosigma angulatum W. S. Adjusted to the upper surface of the shell. The upper parts of the small crests can be seen, and between them are the lines formed by the insufficient focus of the sides or walls of the hexagons.

Fig. 8: Surirella gemma Ehr. Enlarged 1000 times.

Fig. 9: Van Heurckia crassinervis Breb. 2000 times enlarged.

All these photos were taken with the Zeiss lens 1/10 inch, nA 1.63. Monochromatic sunlight. Special compensation eyepiece 12. Condenser 1.6. Inclusion in a medium with refractive index 2.4. Coverslips and flint glass slides with a refractive index of 1.72.

Fig. 7 shows the 19th group of the Nertert's test plate (4443 lines per millimeter).
This image was taken with a 1/12-inch Apochromat, nA 1.4 from Carl Reichert in Vienna.

Source: van Heurck, 1893

[Hobbyst46]

This book by Carpenter is indeed a monumental disposition of microscopy, including auxiliary material such as geometrical optics, physics, mathematics even to the level of tables of logarithms and sines... anatomy and morphology of organisms, antique microscopes...a thermostatted stage based on a Bunsen burner, since electrical power has not yet emerged...

All these photos were taken with the Zeiss lens 1/10 inch, nA 1.63. Monochromatic sunlight. Special compensation eyepiece 12. Condenser 1.6. Inclusion in a medium with refractive index 2.4. Coverslips and flint glass slides with a refractive index of 1.72.
Source: van Heurck, 1893

I wonder how he extracted monochromatic light from the sunlight. I assume he preferred the violet wavelength, since his optics and photography was probably incompatible with UV. But, a true monochromator would provide a very low intensity - except perhaps when the sun stands at the Zenith on a summer day! if he used filters, I doubt that interference filters were known then, so he had to create a bandpass filter from colored glass filters. With all high NA and high RI components he used, he certainly pushed Abbe's and Rayleigh formula to the limit.

[MicroBob]

taken with the Zeiss lens 1/10 inch, nA 1.63. Monochromatic sunlight. Special compensation eyepiece 12. Condenser 1.6. Inclusion in a medium with refractive index 2.4. Coverslips and flint glass slides with a refractive index of 1.72.

Wouldn't this be a nice ebay- of flea-market-find? You open a box and on closer inspection see that it is just this ensemble of rare components? I would even have a use for the sunshine here!

The front lenses of these must have been very delicate due to the little room available for the mounting of them.


Bob

[ImperatorRex]

I wonder how he extracted monochromatic light from the sunlight. I assume he preferred the violet wavelength, since his optics and photography was probably incompatible with UV. But, a true monochromator would provide a very low intensity - except perhaps when the sun stands at the Zenith on a summer day! if he used filters, I doubt that interference filters were known then, so he had to create a bandpass filter from colored glass filters. With all high NA and high RI components he used, he certainly pushed Abbe's and Rayleigh formula to the limit.

At that time monochromatic light have been achived by glas cuvettes that were filled with either a blue copper oxide ammonia solution (blue - violette light for dry plan photo plates) or yellow picric acid solution (used for orthochromatic photo plates).

Some comments on the new monobromnaphthalein objective:
"The lens intensity is very high. We obtained high-contrast negatives from the beads of Amphipleura with a 6-minute exposure time (2000 x magnification and monochromatic sunlight), whereas the previous apochromatosis required at least 10 minutes at 1000 x magnification and very oblique light . "In general, van Heurck assesses this lens as follows:" This lens has the greatest resolution that has been achieved so far. Unfortunately, it is difficult to handle and extremely expensive, as a result its practical value for normal work is not high. Its real scope is the clarification of subtleties that could not yet be resolved with the very best lenses."

[Hobbyst46]

@ImperatorRex - thanks for clarifying. So they managed to keep the photographic setup totally motionless and vibration-less for 10 minutes...we are standing on the shoulders of giants, no doubt.

[75RR]

Hi Bob,

Unfortunately, my browser, which has a .pdf reader extension, crashed from the huge file size before I could locate the plate with the photographs.

https://ia800400.us.archive.org/32/item ... carp_1.pdf

Thanks for the link. Happily I managed to download it.

[desertrat]

On the subject of monochromatic sunlight, I read elsewhere, but cannot now remember the source, that when intense monochromatic light was needed in the late 19th century, a clockwork heliostat would keep a reflected image of the sun positioned over the entrance slit of a monochromator.

I don't know how the monochromatic light was generated for Van Heurck's work. It may have been mentioned in the referenced articles, but I missed it.

[MichaelG.]

There is some useful technical detail here:
https://ia600503.us.archive.org/13/item ... 00heur.pdf

MichaelG.

[Hobbyst46]

There is some useful technical detail here:
https://ia600503.us.archive.org/13/item ... 00heur.pdf

MichaelG.

Thanks MichaelG. Paging this book, I thought of Gandalf reading about the history of the Ring in the dust-covered scrolls in the library of the White City...
Van Heurk mentions three means (on pp132):
1) Briefly - prisms.
2) A solution of the complex ammonium copper sulfate (as mentioned by ImperatorRex above)
3) Several deep-blue filters in series
Nice to know, although these are really obsolete.

[MichaelG.]

Isn't life easy ... now that we have Blue LEDs

MichaelG.

[desertrat]

There is some useful technical detail here:
https://ia600503.us.archive.org/13/item ... 00heur.pdf

MichaelG.

Thanks for the link. Downloaded!

I can transfer the really big .pdf files to another computer with a better reader program, but isn't internet connected.

[wporter]

@ImperatorRex - thanks for clarifying. So they managed to keep the photographic setup totally motionless and vibration-less for 10 minutes...we are standing on the shoulders of giants, no doubt.

Actually, a bit of movement at the beginning & end of a 10-minute exposure might have a lot less blurring effect than it would on a 1/2 sec exposure (with a modern camera & more light).

But as the telescope-using astrophotographers here could point out, they probably used a variation of the "hat trick": temporarily blocking the light path with a hat (piece of black cardboard or whatever), without touching any of the apparatus, during the times the shutter is opened or closed.

[MichaelG.]

For van Heurck's photomicrographic set-up, see p262 of his book [=p284 of the PDF]

MichaelG.

[wporter]

Yes! The hat-trick, via a 'card screen', p.270-271.

These two old books are fantastic. Thanks to MichaelG, MicroBob, and desertrat, who brought them to our collective attention.