Microscopy – The beauty of arranged diatom slides

The Victorians were masters of making arranged diatom slides, and a range of makes produced these from the late 1800s into the 1900s. While there are still some that have been making them recently – Klaus Kemp (now deceased) and Steve Beats, for example – these early examples of arranged slides remain as amazing works of art, and demonstrations of technical expertise. I’ve recently been fortunate enough to acquire a number of these slides and want to share some initial images from them.

The first is one by Watson and Sons Ltd, and is a circular group from St Peters, Hungary (resolution has been reduced for sharing here). I think this one dates to some time around the 1930s.

Watson and Sons circular diatom arrangement

And the slide.

Watson and Sons circular diatom arrangement slide

Imaging the whole circle was a bit of a challenge as it is about 3.5mm across. I ended up using a 3.2x Zeiss Semiplan NA 0.10 objective and removing the condenser from the microscope.

The next is an 80 form type slide by Möller.

80 form type slide by Möller.

This has examples of 80 different diatom species along with a tiny printed grid with the diatoms names. This is about 3mm across. The 2nd diatom from the left of the top row has moved and is now out of focus. This is not hugely uncommon in these old arrangements, but I still find it amazing how one of the diatoms can move through the mountant while all the others remain where they are. One of life’s mysteries…..

Below is an image of one the bottom left diatom – Stephanodiscus nigarae – and a close up on the writing.

The scale bar gives an example of just how small this writing is. From what I can tell the writing is on the underside of the coverslip, and then the diatoms are mounted below that (based on how the image changed as I altered the position of the stage).

Now, how to best share images of these slides in the future? Ideally I’d like to image and share them at high resolution, but my current website isn’t built for sharing many large images. I shall need to have a think about how best to deal with these slides.

As always. thanks for reading, and if you’d like to know more about my work I can be reached here.