A strew slide prepared by John Thomas Norman. I’ll come back to the location in a minute. Nice array of species. Olympus BHB microscope using 450nm LED light. As well as the wider field of view, I imaged one (I think Cocconeis dirupta) using the 63x Leitz Pl Apo 1.4 objective, oil immersion. Olympus Aplanat Achromat condenser, oil immersion, oblique lighting. 2.5x Nikon CF PL photoeyepiece. Monochrome converted Nikon d850 camera. 32 images stacked in Zerene (Pmax).
Cocconeis dirupta W.Gregory 1857. Published in: Gregory, W. (1857). On new forms of marine Diatomaceae found in the Firth of Clyde and in Loch Fyne, illustrated by numerous figures drawn by R.K. Greville, LL.D., F.R.S.E. Transactions of the Royal Society of Edinburgh 21: 473-542, 6 pls [IX-XIV]. Page 491, Plate IX [9], Figure 25.
Ok, the location. At some point, someone has put a label over the original label at the bottom of the slide. Nice. Well done. I assumed there was something useful on that label, and did try and remove the new one, but it was very well stuck. When I held the slide up to the light, it looked like there was some visible text on the original label. It got me wondering if I could image that writing using the microscope. So I put a 1x Olympus S Plan Fl NA 0.04 objective out, and then replaced the filter on the photoeyepiece with a 570nm 10nm FWHM one, and got to work. I took three images focusing on the writing on the original label (so focusing at the interface between the two labels), and pasted these together in Photoshop. I then played around a bit with blurring, sharpening, contrast, curves etc, and got the following.
There is actually some legible text from the label using this approach.
The top line looks to say ‘…..de la…..’. This could be ‘…de la Soaque’, or ‘Soayue’, I am not sure.
The middle line says ‘France’.
The bottom line looks to be a date. Maybe Oct[ober] 1868. I am confident it is 186… something, but less sure of the final digit.
As for the location I have search for ‘diatoms’ and various combinations of ‘de la’ and so far got nothing conclusive. However the diatoms look to be marine (rather than freshwater). I am currently thinking Brittany, or the Atlantic Coast, but to be honest I have no firm possibilities. If you recognise or can read the handwriting better than me, please let me know your thoughts.
As for why on earth someone would put a label over the original one I really can’t fathom it….