Severndroog Castle on Shooter’s Hill is the subject of the April talk from the Greenwich Industrial History Society.

Julia Elton will be speaking online in the evening of Tuesday 8 April, not about the construction of this “elegantly preserved Gothic tower”, but about its role in the development of lighthouses and their illumination.

Meet electronically online at 19:15 on Tuesday; Julia will start talking at 19:30. For details of how to book your free online place, scroll to the end of this post.

This is an untold story, says Julia, who has just completed a PhD, entitled ‘Reflected Glory’, on catoptric lighting.

This is the combination of a parabolic reflector and a smokeless Argand lamp that was used in lighthouses. In fact catoptric lighting forms a well-defined period in the evolution of the science of lighthouse illumination and it survived well into the 20th century, until it was obliterated by the invention of Fresnel’s refracting lens.

Severndroog Castle played a crucial role in its introduction to Britain as this talk will show.

Julia has been specialising in the history of lighthouse illumination for some years. She is a past president of the Newcomen Society for the History of Engineering and Technology and wrote her presidential address on the Fresnel lens.

How to register for this free talk

You can book a place now by emailing greenwichindustrial@gmail.com with the subject line “GIHS Severndroog talk” and we will send you Zoom log-in details just before the talk starts.