15th May 2024 - Bob Dukes & John Hale

Cordite! (Film) and The Story of the
                      Royal Naval Cordite Factory

The Royal Naval Cordite Factory, situated at Holton Heath, north of Wareham, was in existence during and between WWI and WWII. Much of what remains of the 450 acre site is not available to be seen by the public but the makers of the video we are showing had specially granted access during 2011 and 2012.

Many thousands of local people who worked at the RNCF were controlled by the Official Secrets Act with even their own families having little idea of what their relatives were actually working on, or the dangers involved.  Some of the mysteries of what went on behind the “tall black fence” (which still exists) are revealed.

This 40 minute video, produced by John Hale (Greenacre AV Productions), has been updated in 2024 for YouTube and is a short version of the feature length documentary currently on Amazon Prime. It contains an explanation of the chemistry of Cordite, its manufacture and eventual use as a propellant for the Royal Navy, together with an explanation of steps that were taken to protect the Factory from attack by the German Luftwaffe using gun sites and decoys and a description of a huge explosion which occurred in June 1931, killing 10 people.

The morning will start with the video and be followed by a discussion and explanation of the workings of the RNCF factory at Holton Heath using the recollections of Dr Bob Dukes, one of the surviving former employees, who is also one of the presenters featured in our video.

19th June 2024 - John Ives

Astronomy from Space

Up to the 1930’s, astronomy was restricted to observations within the visible range of the electromagnetic spectrum. Then in 1932, a young engineer at Bell Laboratories named Karl G. Jansky tackled a puzzling problem: noisy static interfering with short-wave radio transatlantic voice communications.

After months of tracking the source, he noticed that it shifted slowly across the sky. What could this be? Stumped, he consulted with an astronomer and came to a startling conclusion: It must be coming from beyond our Earth. This was the birth of radio astronomy. Then in 1967, Jocelyn Burnell discovered radio pulsars, really emphasising the importance of observations at wavelengths other than the optical ones.

Our atmosphere is opaque to many of the wavelength ranges of the electromagnetic spectrum, including gamma rays, X-rays, the shorter wavelength ultraviolet, and the longer wavelength infrared rays. So the only way of extending our astronomy observations into these ranges is to place our corresponding telescopes above our atmosphere, for example, in orbit around the Earth.

There are also advantages, that we will talk about, for optical telescopes to be placed above our atmosphere; one example of such a telescope is the Hubble Space Telescope.

Alongside is a composite image of Centaurus A, with images overlaid from optical, X-ray and radio observations, demonstrating how each wavelength brings new information to the overall view of this celestial object.

John’s talk will discuss some of the technical difficulties associated with space-borne instrumentation, together with some of the ways in which observations made in each wavelength range can contribute to our overall understanding of our universe.

17th July 2024 - Richard Cottrell

Food Fraud

It is widely guessed that about 10% of the food and drink we buy is not exactly what we think we are paying for. There is no definite estimate because so much food fraud is difficult, or impossible, to detect. In most cases the result of fraud only hits our wallets, and then not by much. However, invariably, criminals make money. In rare cases the results can be serious, or even fatal for the consumer.

This talk will outline three examples from Richard’s own experience, two of which he researched in depth. One, natural Vanilla, results in murders of farmers in Madagascar; a second, Orange Juice, provides an excellent income for the Sicilian Mafia; and a third, fake Olive Oil, resulted in the largest outbreak of fatal food poisoning in history.

18th September 2024 - James Fradgley

Astronomical Influences on Climate Change:

• Solar Output - Long Term
• Cyclical Variations in Solar Output
• Geological Factors
• Orbital Factors - Galactic
• Milankovitch Cycles - Eccentricity, precession, axial tilt
• Orbital Inclination
• Anthropogenic effects
• Other questions
• Conclusion

16th October 2024 - Chris Morris

Plastic Bicycles

The Itera Plastic Bicycle was conceived in the early 1980s by ex-Volvo employees, with encouragement and loans from the state-owned bank PK-Banken. Volvo had been experimenting with a plastic mini car at the time. The idea here was to design a revolutionary new bike in Gőteborg (Gothenburg) and mass produce it inexpensively in Vilhelmina, Lappland (Lapland), where employment was needed up in the far north. This was the first time in the world a plastic injection moulded bicycle was mass-produced.

Launched in 1982, with a clever advertising program, the Eternal Machine (Evighetsmaskinen in Swedish) alluded to the fact that the frame could never rust. It was marketed as a mail order flat-pack which the owner assembled IKEA style.

So far so good so what could possibly go wrong?

Chris Morris became interested in the details of bicycle technology in the last decade or so. He first volunteered in 2011 at the Pedal Depot (a not-for-profit bicycle cooperative) in Vancouver, Canada, overhauling many older bikes for sale.

In 2015 he was appointed a director and over time he wrote, presented and had published over a dozen international papers on various aspects of bicycle design. The presentation locales included the United States, UK, Sweden, Belgium, Holland, Germany and the Czech Republic.

Since retiring to Swanage in late 2019, Chris has had several papers published in English and Italian cycle magazines and participated in various local bicycle-themed pop-up stands at cultural events in Corfe and Swanage. Last Spring he was in Cremona, Italy to present a paper entitled A Shifty Business on the varied approaches to shifting hub and bottom bracket gears.