As my time working with UCL’s lantern slides draws to a close, I thought I’d reflect on some of the things I’ve discovered over the past few weeks. (To learn what lantern slides are, and why UCL has accumulated thousands of them, click here).

Slide EE703 – A Vreeland oscillator, 
or just another electric circuit
to the unaccustomed eye.

The majority of  the slides in the UCL Science and Engineering collection are, unsurprisingly enough, about Engineering. Electrical Engineering to be precise. I must say that, having not had a single Physics lesson in the past six years, the prospect of cataloguing slide after slide of what looked like identical electric circuits was not exactly my cup of academic tea. But I soon learnt that there is a lot more to ElecEng (as it is apparently abbreviated) than alternators, resonators, oscillators and commutators. In particular, I became interested in UCL’s very own Sir John  Ambrose Fleming, founder of England’s first University Department of Electrical Technology, inventor of the thermionic valve and Pender Professor at UCL for three decades.

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Grant Museum magic lantern slide LDUCZ-299 showing craters on the lunar surface

The UCL Grant Museum and the Science and Engineering Collections currently have several thousand magic lantern slides that relate to subjects as diverse as telegraphy, astronomy or Australian coral reefs; but which for the most part have been consigned to gathering dust in splintering wooden boxes. I, however, have spent the last few weeks sorting, auditing and cleaning hundreds of these slides, and I am now rather well acquainted with these little glass squares.

Example of a 19th century magic lantern slide projector from the UCL physics collection. This example was used as a sort of overhead projector but others were designed to project across a lecture theatre or hall

Magic lanterns were first developed in the 17^th century as one of the earliest image projectors. While the device itself has evolved, the concept has remained the same: A combination of lenses and a light source are used to enlarge the images found on glass slides (each about the size of a Post-it) and project them onto a wall or screen. Magic lantern slides, hence, can be described as a kind of ancestor to the Kodachrome slides used in slide projectors, or even present-day PowerPoint slides. (more…)