A travelling scientist is shown demonstrating the formation of a vacuum by withdrawing air from a flask containing a white cockatoo, though common birds like sparrows would normally have been used. Air pumps were developed in the 17th century and were relatively familiar by Wright's day. The artist's subject is not scientific invention, but a human drama in a night-time setting.
The bird will die if the demonstrator continues to deprive it of oxygen, and Wright leaves us in doubt as to whether or not the cockatoo will be reprieved. The painting reveals a wide range of individual reactions, from the frightened children, through the reflective philosopher, the excited interest of the youth on the left, to the indifferent young lovers concerned only with each other.
The figures are dramatically lit by a single candle, while in the window the moon appears. On the table in front of the candle is a glass containing a skull.
Miranda Hinkley (in the Gallery): I’m standing in front of an 18th-century painting which is a moment frozen in time. There’s a group of figures all gathered around a kitchen table, all the members of the family and in the centre is a rather enigmatic looking character with lots of white long bushy hair, who appears to be conducting some kind of experiment on a cockatoo that’s trapped in a bell jar. Jenny, what’s going on here? Who is this character in the middle?
Jenny Uglow: The man in the middle is a travelling lecturer or demonstrator. He’s demonstrating one of the exciting aspects of the demonstrator’s art, which is the air pump. And he’s got a very large glass vessel poised on a column and in the glass vessel is a bird and the bird is fluttering and near to death because from the pump down below – you can see the handle, glistening handle, next to those pistons – he’s extracted all the air from the glass, but his hand is poised just above it to let us know that if he pulled the stopcock at any moment, he could flood the glass vessel with air again and the bird would revive.
Miranda Hinkley: So this was painted by Joseph Wright 'of Derby' who… there are a number of works by him dealing with the advance of science and the industrial revolution…
Jenny Uglow: Yes, Joseph Wright grew up in Derby which was one of the main centres of the industrial Midlands. It had instrument makers, it had silk mills, and he was fascinated as a child by mechanics and he went off as a child to be apprenticed as a painter but many of his friends when he came back to Derby were experimental scientists or were industrialists so they were making very important and exciting discoveries.
Miranda Hinkley: So Wright would have understood quite well what was happening in this painting in this process.
Jenny Uglow: Yes, Wright would understand absolutely the process that he’s showing. He’d have seen demonstrators do it, but also he asked his friends for help when he didn’t understand things. So he’s not just making evocative pictures, he’s showing something that he really understands.
It’s quite technical – there are a lot of other things in the painting which are to do with pneumatics. It’s a lecture on pneumatics, how the world changes if you do remove the air – they’ve got these Magdeburg spheres here, which you put together and if you suck the air out of them they just cling to each other and you can’t separate them, and this mysterious object in the jar, which people used to think was a skull, a sort of memento mori, a reminder of death, and then people said no it’s a sheep’s bladder, and somebody very persuasively said actually it’s human lungs. And again that goes with the feeling that the painting is actually about air and the power of air because Wright was an asthmatic. It was desperately important to him the whole act of breathing and one that was very painful and mysterious and precious.
Miranda Hinkley: This sort of a scene is quite alien to us today in the sense that you don’t have wandering scientists who come and reveal the wonders of nature to you in your own home anymore. But I think there’s something here about people’s attitudes to science and kind of different feelings towards it.
Jenny Uglow: Yes, of course there is. It’s actually ever since this period that scientists have been thought of as rather dangerous, partly because the scientific endeavour, the rationalist endeavour, was associated with the philosophes in France who were behind the French Revolution. So that when the French Revolution came they actually turned on the scientists, the natural philosophers, in their midst and said – ‘well, look what that comes to’. And scientists were then, as it were, set apart – mysterious experimenters.
People always think that you’re dabbling with the secrets of nature. It’s very like the things that frighten us today, like cloning, you know, like creating alien forms of life. This is very dangerous and yet if you’re going to cure something like Wright’s own asthma, you’ve got to know about the mechanics of breathing and of air, so it’s a good thing. We want the advantages of science but we’re always a bit frightened that we’re tapping into a power that could actually hurt us.
Miranda Hinkley: There’s something really striking about this painting. It’s not just the arrangement of the figures and the way he’s captured everyone’s thoughts so perfectly in their faces, it’s also the contrast of light and dark and the sort of light of knowledge kind of penetrating the surrounding darkness…
Jenny Uglow: It is. And if you think of it as a kind of demonstration it’s also like a bit of theatre, isn’t it. It’s like something glowing on a stage and it pulls you in. There’s… it makes you think of earlier paintings, which are actually not scientific paintings, but religious paintings, which have this glowing mystery at their heart. And in the National Gallery, there’s a little early painting where the Christ Child in the manger is actually glowing almost, exactly like this, and the faces are lit up watching him, so this is like a new miracle, this is a new way of understanding the meaning of life.
From The National Gallery Podcast: Episode Nineteen, May 2008