We also looked at a report about the development of toroidal propellers. These are an advancement on the old screw propeller and can both decrease the noise of a screw propeller and increase its efficiency by a significant factor. They are mostly being used in noiseless drones. The cost of converting ships to toroidal propellers has so far held up their use but it will happen.
In the first half of the session, we watched a BBC documentary on the history of Electricity entitled Shock and Awe. This covered the full history from the first example of watching the transfer of positive and negative charges that produce a spark to the realisation that electricity has some connection with the movement of electrons. The documentary showed examples of all the significant developments and we actually witnessed how electricity was first produced inside a vacuum jar. The amazing thing was that you could actually see electricity. This as you can imagine was spectacular.
At our next session we will continue to follow in part the exploration of electricity.
Neville Gibb