South Coast autumn meeting
Saturday 16th October 2021
This was our first meeting in the Main Hall of the Village Hall at Langton Matravers in Dorset since April 2019, because of the Covid-19 epidemic, and was organised by Pam Hamer, who has taken over responsibility from Derek Stevens and Brian Darnton.
Langton Matravers Village Hall
Joan Bingley was promoting a new Quekett project on the composition and invertebrates of bird nests. She showed a nest of a robin, and a comparison of the composition of that nest and one of a blue tit. Joan also brought a Tullgren funnel that Graham Matthews had designed for extracting invertebrates from nests, and a book, Nests by Susan Ogilvy, with paintings of the nests of 28 British birds.
Joan Bingley’s birds’ nests exhibit
Joan also brought the natural history specimens that she had shown at the Sidmouth Science Festival a week earlier. Her whole specimens included a snake skin, a lichen, part of a wasp nest, and a blob of resin from a tree. Her slides included sand and parts of plants and mosses, with a Chinese inspection camera to show them on a television.
Joan Bingley’s natural history display
Joan Bingley’s slides
Joan Bingley’s specimens
Adrian Brokenshire brought along a wooden cabinet of nicely-prepared forams and shells from sand (on black and white backgrounds) that we were able to admire using his Meiji BM long-arm stereomicroscope. As usual, Adrian was very kindly giving away bags of shell sand and other materials, including some collected this year from near Trevose Head in Harlyn Bay on the north coast of Cornwall. Adrian would appreciate samples of shell sand or coral sand from anywhere in the world.
Adrian Brokenshire’s exhibit
Pam Hamer and Adrian Brokenshire
Some of Adrian Brokenshire’s mounted specimens
Adrian Brokenshire’s specimens on black background
Some of Adrian Brokenshire’s free samples
Sand from Harlyn Bay, Cornwall
Brian Darnton showed an LED torch with a high CRI (almost white light) that he had modified with an external intensity control to make it easier to use with a microscope.
Brian also showed a lot of slides that he had made, mostly of forams. The foram slides were mainly from 2 sources, North Cyprus (collected by Brian) and the HMS Porcupine expedition. HMS Porcupine was chartered by the Royal Society in 1869 to investigate the deep sea bed to the west of Ireland, looking for living organisms below 600 m, and they found organisms as deep as 3000 m. Brian obtained Foraminifera from the expedition that had belonged to Alfred Merle Norman. Brian provided a black and brass monocular Spencer microscope so that we could examine the slides.
Joan Bingley and Brian Darnton
Jeremy Poole and Brian Darnton
Some of Brian Darnton’s slides
Some of Brian Darnton’s foram slides
Brian was very generously giving away some of his foram slides from North Cyprus and the HMS Porcupine expedition, and Alan Wood had a look at them using polarised light.
Some of Brian Darnton’s free foram slides
Foram from North Cyprus (length 1.35 mm, crossed polarisers + full-wave retarder)
The HMS Porcupine expedition was reported in Nature and in Proceedings of the Royal Society of London in 1869:
- The Deep-Sea Dredging Expedition in H.M.S. “Porcupine” [Dec. 2, 1869, by J. Gwyn Jeffreys]
- The Deep-Sea Dredging Expedition in H.M.S. “Porcupine” [Dec. 9, 1869, by J. Gwyn Jeffreys]
- Preliminary Report of the Scientific Exploration of the Deep Sea in H.M. Surveying Vessel ‘Porcupine’, during the Summer of 1869 [by Dr Carpenter, J. Gwyn Jeffreys & Wyville Thomson]
Pam Hamer’s main exhibit was about microfossils in rocks, and she provided two microscopes connected to laptop computers so that we could examine the rocks that she has ground and polished to make the fossils visible. The microscopes were a digital Dino-Lite Pro (using DinoCapture software) and a Vickers polarising microscope with a Brunel eyepiece camera (using ToupView software). Both microscopes had polarising filters to reduce reflections from the polished rock surfaces.
Derek Stevens, Jacky McPherson and Pam Hamer
Jacky McPherson and Pam Hamer
Microfossils in rocks
- Read Pam Hamer’s notes: More investigations of microfossils in rocks!
Dino-Lite Pro digital microscope on small tripod
Vickers polarising microscope with reflected illumination
Pam also showed printed copies of the free Quekett leaflets, including the new one on Rocks and Minerals. They are available as free downloads from the Quekett website.
Quekett leaflet: Rocks and Minerals
Pam also demonstrated how she cuts a flat surface on rocks and polishes them to reveal microfossils, using Rolson diamond whetstones, T-Cut Rapid Scratch Remover and sandpaper.
Diamond whetstone set and scratch remover
Grenham Ireland brought live specimens collected from Poole Harbour and displayed them with dark-ground illumination using a Chinese inspection camera (mounted on a sturdy copying stand) linked to a monitor. Grenham is familiar with most of the plankton from the harbour, but his sample included a couple of creatures that he did not recognise.
Grenham also displayed 2 posters, one about migration of eyes of plaice (Pleuronectes platessa) and the other about the ctenophore Pleurobrachia pileus.
Grenham Ireland’s exhibit
Grenham Ireland and Jeremy Poole (right)
Jeremy Poole came along with some display panels on which he mounted scanning electron micrographs of pollen, together with colour photos of the plants.
Jeremy also brought some copies of his self-published book, Big Pictures of Small Things: A Personal Selection of Scanning Electron Micrographs. The book includes some 3D anaglyphs, so it comes with red-cyan glasses. If you would like to buy a copy, please contact Jeremy Poole.
Jeremy Poole’s SEMs of pollen
Derek Stevens admiring Jeremy Poole’s SEMs of pollen
David Spears showed four of his coloured scanning electron micrographs
Some of David Spears’ coloured SEMs
Derek Stevens had planned to show Haematococcus pluvialis, rotifers and other organisms from his bird bath, using an eyepiece camera on a small Bresser microscope linked to a television. Unfortunately, the eyepiece camera was not working.
Grenham Ireland and Derek Stevens (right)
Last month, Derek used the Club’s Facebook Group to offer a Gallenkamp ‘Junior’ centrifuge, a Cambridge rocking microtome, a Singer micromanipulator, and stands for cameras by Baker and Vickers. Jacky McPherson was interested in the micromanipulator and combined collecting it with a visit to the meeting. The other items are still available; if you are interested, please contact Derek Stevens.
Jacky McPherson with Singer micromanipulator
Alan Wood brought his Olympus CH-2 microscope, BH2-KP intermediate polarising attachment and full-wave and quarter-wave tint plates (retarders), and showed us how to compare the expensive Olympus tint plates with some of his makeshift retarders cut from a variety of plastic films.
Alan Wood’s demonstration
Olympus full-wave and quarter-wave tint plates
Olympus BH2-KP polarising attachment with retarder
It is easy to rotate the makeshift retarders (assorted plastic films attached to card annuli) because they just sit on the light output in the base of a microscope. The Olympus tint plates cannot be rotated, which limits their use for pictorial effects.
Alan showed photomicrographs taken through crossed polarisers plus various retarders of a thin section of quartz diorite by an unknown mounter, and he demonstrated the effects of the retarders.
Thin section of quartz diorite
Quartz diorite, crossed polarisers plus Olympus quarter-wave retarder
Quartz diorite, crossed polarisers plus Olympus full-wave retarder
Quartz diorite, crossed polarisers plus makeshift retarder
Quartz diorite, crossed polarisers plus makeshift retarder
Some of the makeshift retarders gave interesting results, but none of them were as spectacular as the Olympus full-wave retarder. The Quekett Shop sells 2-inch squares of full-wave retarder that should provide very similar results to the expensive Olympus version.
Alan tried the foram slides that Brian Darnton was giving away, and found that some of them showed colours under crossed polarisers and a retarder.
Foram from North Cyprus (length 1.35 mm)
Exhibits and members in the Main Hall
Our thanks to Pam Hamer for organising another enjoyable and successful meeting, and to the people who set out and packed away the tables and chairs.
Report and photographs by Alan Wood