Crystals have always provided interesting and attractive subjects for the microscope, and this was known as well to the Victorian microscopes with their early Nicol prism polarisers ( http://en.wikipedia.org/wiki/Polarizer ), as it is today. The heyday of commercial slide preparation provided many fine examples of crystal mounts that are still in good condition over 100 years later.
The Victorian microscopists were also obsessed with novelty, and clearly having the latest and most obscure chemical crystal mount had the same cachet as having the latest fossil diatom discovery from the Oamaru diatomite deposit, or the latest most gorgeous arranged mount of butterfly scales. Many of the consumers of Victorian commercial mounts were people of means, and very considerable sums by the standards of the time, were charged for the latest novelty.
Really interesting old slides of crystals are sought after and collected, but as someone more interested in the microscope worthiness of an old slide, I tend to look for slides with a little minor damage here and there which renders them less attractive to out and out collectors. I recently obtained a rather tatty (from a collector’s perspective) slide by Victorian mounter A. C. Cole marked Yttrium chloroplatinate. Unlike most similar crystal slides of the time, the background is black and the slide is marked ‘Lieberkühn’ , an early form of ‘top’ or incident illumination http://www.microscopy-uk.org.uk/mag/art ... incid.html . After a careful clean of the coverslip surface, I looked at this slide on my Ortholux 1 with the Leitz Ultropak incident light attachment fitted http://micromundos.dyndns.org/manuals/L ... tropak.pdf . This uses special objectives, designated UO which direct a concentric focused beam of light onto the subject and collect the reflected light. My Ultropak has a built in polariser and also the provision for filters, so a second polarising filter and retarder of suitable diameter can be fitted. The analyser mounts over the tube lens inside the main body of the microscope. This system is ideal for polarised incident light work. I took a look at my Yttrium chloroplatinate slide using the lowest power UO objective I have, a X6.5, using crossed polars, with and without a rotatable Perspex retarder.
The crystals were still beautiful to look at despite their age and rotating the retarder produced interesting changes from mainly red and green to shades of yellow and deep blue/purple.
I wondered how this chemical curiosity might have found its way onto a commercial slide for a Victorian collector. A bit of detective work suggests the potential source is one Per Teodor Cleve http://www.nndb.com/people/143/000213501/ Swedish chemist, discoverer of Holmium and Thulium, and fanatical documenter of the properties of the rare earth elements. In the Chemical News of April 10th 1874 he reports the synthesis of Yttrium chloroplatinate together with other obscure rare earth element salts. http://books.google.co.uk/books?id=XPrm ... te&f=false Is it fanciful to suggest Cole writing to Cleve, perhaps some money changing hands, and Cole receiving a small quantity of this ultimate chemical curiosity? I like to think something like that happened.
Subsequently I came across this nice article on Victorian crystal slides which started me looking for crystals of metal platinocyanide salts http://www.microscopy-uk.org.uk/mag/art ... rian3.html but that needs a another thread.
Rare Metals, Obscure Chemistry and Victorian One-upmanship!
Moderators: rjlittlefield, ChrisR, Chris S., Pau
- Cactusdave
- Posts: 1631
- Joined: Tue Jun 09, 2009 12:40 pm
- Location: Bromley, Kent, UK
Rare Metals, Obscure Chemistry and Victorian One-upmanship!
Last edited by Cactusdave on Sun Feb 02, 2014 3:05 am, edited 2 times in total.
Leitz Ortholux 1, Zeiss standard, Nikon Diaphot inverted, Canon photographic gear
-
- Posts: 713
- Joined: Thu Mar 14, 2013 11:40 am
- Location: Atlanta, GA, USA
- Cactusdave
- Posts: 1631
- Joined: Tue Jun 09, 2009 12:40 pm
- Location: Bromley, Kent, UK
Thanks guys. I enjoyed looking at this slide, and the challenge of illuminating and photographing it as well as trying to find out a little about Yttrium chloroplatinate. To someone with a science background it seemed such a wildly exotic choice of subject for a simple crystal preparation, and it was interesting to understand the economic factors involved and to try to work out where the sample had come from.
Leitz Ortholux 1, Zeiss standard, Nikon Diaphot inverted, Canon photographic gear
-
- Posts: 2982
- Joined: Fri Nov 20, 2009 11:24 am
- Location: Panama
- carlos.uruguay
- Posts: 5358
- Joined: Thu Feb 23, 2012 8:05 pm
- Location: Uruguay - Montevideo - America del Sur
- Contact: