Projecting Knowledge: The Optical Lantern and Science Communication, 1880s-1940s with Dulce da Rocha Gonçalves, Nico de Klerk and Frank Kessler (Brepols, 2026)

Well, it's basically a slide projector.

You may remember from your childhood when your parents took photos during the holidays and projected them afterwards.

And so, in a way, the optical lantern is a predecessor to that technology.

And it goes back to the 17th century with a German monk, Athanasius Kircher, who allegedly not necessarily invented it, but presented the first representation in an image of a magic lantern, which was the term used then mainly.

As in the 19th century, the uses that were being made of the projection lantern became more and more to illustrate lectures for knowledge communication, then the term magic lantern, in a way, was thought to produce the wrong connotations.

And so in different countries, we can see that other names are being used increasingly.

So in the United States, it's stereopticon.

In Britain, mainly optical lantern.

And in Germany and other countries, Psyopticon, which is actually the name of a specific type of projection lantern, which was used often in education.

So basically, it's indeed a slide projector.

And it's not by accident that for PowerPoint, we still talk of slides.

So there's a long, long history of using the projected image to illustrate lectures of all kinds.

So I see I've betrayed my Britishness by calling it the optical lantern throughout my introduction then.

So let's talk about some of the people who are kind of witnessing these, I guess, slide to slide presentations then from the optical lantern.

So your book, your contributors look at both mass audiences, but also niche audiences, imagined audiences in some chapters and actual audiences.

So...

Who were these audiences? Who were the people seeing these optical lantern presentations? And what do these different types of audiences tell us about the optical lantern?

I think there were very varied audiences.

It depended often on the topic.

For instance, and this is outside strictly scientific communication, but there was also applied or practical scientific topics like how to cure or how to protect yourself against tuberculosis, for instance.

These, for instance, were mainly addressed to a working class audience.

The same goes for very popular genre at the time, late 19th and also first half of the 20th century, is alcohol abuse and how to combat that.

Then there were specific institutes besides the fact that lanterns could be used in any venue It was possible, so there was never, as Dulce also has written about, there was never a dedicated venue for the lantern, like you have a cinema theater or a stage theater.

So there were cafes, there were associations, buildings, whatever was available, whatever they could lay their hands on, so to speak.

And there were specific institutes such as what we call in Dutch Volksuniversiteit, night schools actually, for adults to improve education.

Well, it's basically a slide projector.

You may remember from your childhood when your parents took photos during the holidays and projected them afterwards.

And so, in a way, the optical lantern is a predecessor to that technology.

And it goes back to the 17th century with a German monk, Athanasius Kircher, who allegedly not necessarily invented it, but presented the first representation in an image of a magic lantern, which was the term used then mainly.

As in the 19th century, the uses that were being made of the projection lantern became more and more to illustrate lectures for knowledge communication, then the term magic lantern, in a way, was thought to produce the wrong connotations.

And so in different countries, we can see that other names are being used increasingly.

So in the United States, it's stereopticon.

In Britain, mainly optical lantern.

And in Germany and other countries, Psyopticon, which is actually the name of a specific type of projection lantern, which was used often in education.

So basically, it's indeed a slide projector.

And it's not by accident that for PowerPoint, we still talk of slides.

So there's a long, long history of using the projected image to illustrate lectures of all kinds.

So I see I've betrayed my Britishness by calling it the optical lantern throughout my introduction then.

So let's talk about some of the people who are kind of witnessing these, I guess, slide to slide presentations then from the optical lantern.

So your book, your contributors look at both mass audiences, but also niche audiences, imagined audiences in some chapters and actual audiences.

So...

Who were these audiences? Who were the people seeing these optical lantern presentations? And what do these different types of audiences tell us about the optical lantern?

I think there were very varied audiences.

It depended often on the topic.

For instance, and this is outside strictly scientific communication, but there was also applied or practical scientific topics like how to cure or how to protect yourself against tuberculosis, for instance.

These, for instance, were mainly addressed to a working class audience.

The same goes for very popular genre at the time, late 19th and also first half of the 20th century, is alcohol abuse and how to combat that.

Then there were specific institutes besides the fact that lanterns could be used in any venue It was possible, so there was never, as Dulce also has written about, there was never a dedicated venue for the lantern, like you have a cinema theater or a stage theater.

So there were cafes, there were associations, buildings, whatever was available, whatever they could lay their hands on, so to speak.

And there were specific institutes such as what we call in Dutch Volksuniversiteit, night schools actually, for adults to improve education.