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Royal Institution, London, April 2005
 Speaker's Notes
I have to say that it is a rather awesome experience to be standing in the place where Michael Faraday once stood. Faraday is famous for having discovered how to manufacture electricity. My main claim to fame is having discovered the best way to dunk a biscuit. What I do have in common with Faraday is that I have devoted my life to science (not all of it concerned with biscuits) and that I now spend a lot of my time trying to share what science is about and making it accessible to others.
Faraday did this by talking about the science of everyday things. He did it in this very room when he gave a series of lectures on The Chemical History of a Candle that attracted the cream of Victorian society. I'm pleased to notice that I have also attracted the cream of society, although I'm going to talk to you about a somewhat different topic. What I'm going to talk about is how difficult it can be to distinguish the brilliant from the bizarre (except in hindsight) and how many of the people who gave us our major scientific ideas had to face ridicule, persecution and worse because their ideas went against the accepted "common sense" of the time.
Electricity
In honour of Faraday let's start with the subject of electricity. Faraday constructed his first working model of a dynamo in 1832, but people had been manufacturing electricity by less effective means long before that. Most of these involved rubbing two insulators together so as to rip the electrons off the surface of one and deposit them on the other, although of course they didn't know that that was what they were doing at the time. One of the earliest was a machine invented by a German Professor of Languages called Johann Winkler in 1744 which he used to rub a beer glass against his hand to generate the electricity.
Fun with machine
People had a lot of fun with these machines
Electric kiss, etc.
especially when a Dutchman called Pieter von Musschenbroek at the University of Leyden in Holland invented a way to store the electricity as it was generated. It was called the Leyden jar, and one of the tricks was to get a line of people holding hands and then get the two end people to touch the inside and outside contacts of the jar respectively so that an electric current passed along the whole line and everybody jumped with the shock. The one I really like was where this was done to a line of Carthusian monks that was over a mile long!
Now for goodness sake don't try this at home, because Leyden jars can easily deliver a fatal belt, and people have been killed by carelessly touching them even when they have been sitting around for a long time.
Franklin
One of the people who experimented with the Leyden jar was Benjamin Franklin, and this is my first example of someone who was laughed at for suggesting an idea that went right against the common sense of the time. Franklin's controversial idea was that lightning was a form of electricity, which seemed ludicrous to most scientists, because the tiny sparks that they could then make by rubbing two insulators together seemed in no way related to the massive power of a lightning bolt, and in any case how could a cloud manufacture so much electricity? In fact we know now that it is manufactured in much the same way by water droplets rubbing together, but they didn't know this then, and the best guess was that lightning was some sort of heavenly fire. This is an idea that goes right back to the Greek playwright Aristophanes, who thought that the accompanying thunder was a heavenly fart. I don't think many people believed this in the 1700s, but Franklin says in autobiography that his alternative idea was "laughed at by the connoiseurs", and the laughter was especially loud here in England, because Franklin was American and this was the time of the American War of Independence.
The laughter got even louder when Franklin suggested that he could prove his point if someone would only be bold enough to draw some lightning from a cloud and store it in a Leyden jar. Most of his contemporaries thought that this was a totally crackpot idea, but a Frenchman called Thomas-Françoise D'Alibard took it seriously. Here is his description of what happened, which has a very French flavour:
"In a garden at Marly, six leagues from Paris, he set up an iron rod, an inch wide and forty feet long, pointed with brass. Having no cake of resin with which to insulate it from the ground, he used a stool which was merely a squared plank with three wine bottles for legs. At twenty minutes past two there was a single clap of thunder followed by hail. D'Alibard was just then absent. A former dragoon named Coiffer, left to watch the experiment, heard the thunder and hurried to the rod with an electric phial [i.e. a Leyden jar]. Sparks came from the iron with a crackling sound. Coiffer sent a child for the prior of Marly, who had heard the thunder and was already on his way. Meeting the child in the road, he began to run. The villagers, believing that Coiffer had been killed, ran after the prior through the beating hail. Terrified, they stood back ten or a dozen paces from the rod, but in broad daylight they could see the sparks and hear the crackling while Raulet the prior drew off all the electric fire. He sat down and wrote a letter which Coiffer took to D'Alibard, who three days later made his report to the Academie Royale des Sciences. Following the course which Franklin had outlined, he said, he had arrived at incontestable proof. Franklin's idea was no longer a conjecture."
Franklin didn't know anything about this for quite a while, and tried his own experiment that we all know about where he flew a kite in a lightning storm and drew sparks from a metal key attached to the bottom of the string. But the French experiment actually came first. You should also know that the traditional picture of Franklin standing out in the open getting soaked while he was flying his kite is a load of rubbish. He was safely inside and flying the kite through an open window so that the bottom of the string stayed dry.
 One of the big problems in Franklin's time was how to protect churches against lightning strikes, not just because they were especially vulnerable because of their high steeples but because most of them had gunpowder stored in their crypts! The main way of trying to protect them was for the bellringers to rush up the stairs and start ringing the bells to break up the lightning flashes, which didn't do much for the lightning and wasn't too good for the bellringers either when the lightning struck. So Franklin came up with idea of protecting the buildings by putting pointed lightning rods on them, but his reason for doing this was entirely false. He had noticed that you could discharge a Leyden jar by bringing a grounded pointed wire near it without actually drawing a spark, and his idea of using sharply pointed lightning rods was to do the same thing with clouds and slowly drain the electricity from the cloud without causing a lightning flash.
Benjamin Wilson
It seemed like common sense, and Franklin's reputation was so high by this time that even people in England believed him, and the Royal Society proceeded to have sharply pointed lightning rods installed on buildings like the gunpowder magazine that was then at Greenwich. Only one person thought that Franklin's reasoning was nonsense, and that was an Englishman called Benjamin Wilson, who was the court painter to George III. He was also an amateur experimenter with electricity who was good enough to have been elected to the Royal Society, but his fellow Fellows just laughed at him when he said that no-one knew how much electricity there was in a cloud and that a pointed lightning rod could well draw the lot down at once but would not be thick enough to carry all of it safely to ground.
We now know that pointed lightning rods do draw lightning bolts, and that clouds contain quite a lot of electricity – a single lightning stroke can deliver 100 thousand million watts, but it's all over in a thousandth of a second, although in that time lightning can have some very peculiar effects. There was a case in 1895
Quakertown Story as Given in Weighing the Soul
Wilson thought that he had really made his point when lightning hit the Greenwich magazine but missed the lightning rod entirely and blew a section off the roof nearby, but instead of listening to him his fellow Fellows responded to this near-catastrophe by having another 49 pointed rods installed!
The story takes some very peculiar turns after that, because Wilson's response to being laughed at was to build a scale model of the Greenwich magazine, fit it with sharp and blunt lightning rods and bombard it with artificial lightning in an attempt to prove his point. He even charged admission for people to watch the experiment, which was a bit of a mistake, because one observer caught him faking the experiment and reported it. You'd think that that was that, but remember he was the court painter and had the ear of King George III, who was hardly likely to support American innovations, having just lost America in the War of Independence. His scientific reputation might have been ruined, but he nevertheless only had to have a word with the King for the King to have a word with the Royal Society and order that Franklin's lightning rods should be removed from all Royal Buildings or fitted with cannon balls to make them blunt.
Wilson has also had the last laugh from beyond the grave, because recent experiments in America have shown that slightly blunted lightning rods are better than pointed ones at drawing lightning.
Galvani
Franklin also had a point about the electric atmosphere generated by clouds, and this was used by another of my heroes, the Italian anatomist Luigi Galvani, who was looking at the effects of electricity on the muscles of dead frogs. He knew all about these experiments where you could make people jump by hooking them up to a Leyden jar, and he was also aware of experiments where this was being studied more scientifically, say by touching the contacts to someone's leg and making it kick. He found that you could get the same effect on the muscles of a dead animal using electricity generated by a machine based on Winkler's (this was way before Faraday) or even from the electric atmosphere generated by distant lightning. Where he got into trouble with his contemporaries was when he found that he make a dead frog's leg kick without any external source of electricity at all, just by touching the leg in two different places simultaneously with a bit of wire. To him this meant only one thing – that the animal must be making its own electricity, even after it had died.
Well the physicists of his day were outraged. Electricity was their province, made by their methods, and they weren't going to have animals going off and making it for themselves. The leading Italian physicist was a man called Alessandro Volta, and he set out to prove that Galvani must have been wrong. The first thing that he found was that Galvani hadn't just used one piece of wire; he had used two bits of linked wire made from different metals. So Volta thought that this must have been the source of the electricity, and to prove his point he came up with the very clever idea of replacing Galvani's frog with something totally inanimate to see if this still produced electricity. The something that he used was actually a piece of cardboard soaked in salt solution. He cut the cardboard into discs, and made a pile of these interleaved alternately with discs of silver and zinc. When he touched the two ends and received a shock, he knew that his pile was producing electricity. And that was how the battery came to be invented, when Volta used cardboard to replace a frog. Only in those days it was called a Voltaic pile.
Volta's experiment had a huge impact, and the result of it was that Galvani's ideas were totally dismissed and when he died some ten years later he was still regarded as a crackpot It was over a hundred years before scientists found that he had been right after all, and that animals do make their own electricity – in fact, that's how our nerves and muscles work.
Aldini
The only person who had faith in Galvani was his nephew Giovanni Aldini, and after Galvani died Aldini travelled the world giving demonstrations of the effect of electricity on human corpses. These didn't actually prove anything, but they gave the audience a lot of thrills, especially when he applied a current to the leg of a recently executed murderer in front of an audience at London's Royal College of Surgeons, and corpse responded by vigorously kicking one of his assistants out of the way. That was nothing compared to a similar demonstration that a Scottish doctor gave in Glasgow some years later, where he applied the electricity to the corpse's finger and the corpse responded by pointing at members of the audience. They thought that their sins had found them out and they scattered wildly to avoid the pointing finger.
It's rather ironic, incidentally, that Aldini used a Voltaic pile to produce these effects.
Duncan MacDougall
Speaking of corpses, one of the most interesting experiments that I came across when I was writing this book was the one that eventually gave it its title. This was where an American doctor called Duncan MacDougall attempted to weigh the human soul by putting a dying patient on a set of scales and watching to see if there was any change in weight when the patient died.
Now this isn't a new idea. Egyptian tomb paintings …. Middle ages
MacDougall Story and My Explanation from Weighing Of Heat
Galileo
Speaking of souls, does anyone know what Galileo's first academic project was? He was commissioned by the Florentine Academy to use his mathematical skills to calculate the dimensions of Hell.
He had something to work on, because Dante had described what Hell looked like in his poem The Inferno, which divided Hell into nine levels. In fact, there is a very interesting Net test that you can take to find out which level you belong in. I belong in Circle Six among the heretics, where the guilty fry and the sinners cry.
Galileo worked out from Dante's poem that Hell must have the shape of an ice-cream cone, with the point at the centre of the Earth and the roof having the form of a dome that was part of the Earth's crust. It didn't seem in the least bizarre to him to be doing this calculation, which just goes to show how difficult it can be to distinguish the brilliant form the bizarre. His main problem was in working out how thick the roof should be to bear its own weight, and what he did was to scale up Brunelleschi's famous dome in Florence. It was only after he had got a prestigious University job as a result of his calculations that he realized that the calculations were wrong, and that you couldn't just scale up structures that way. So he did just what I am afraid that I would have done; he kept his mouth shut while he tried to work out what the right scaling law was, and that took him the rest of his life. Eventually he did get it right, and he wrote down the correct scaling law that engineers still use in designing structures today.
I don't have time to go into all of the other things that happened to Galileo, although I would point out that the thing that got him into most trouble during his lifetime was going against things that his fellow academics regarded as common sense. One that you all know about was when he went against the idea that the Earth is the centre of the Universe and got into trouble with the Pope, but when he was younger he got into just as much trouble, and in fact lost his University job, for going against the common sense notion that things only move if they are pushed or pulled. The full story of that is in the book, together with many other stories that I haven't had time to talk about, and the main moral of all of them is that Nature often doesn't obey common sense, and that as the result of the efforts of people like Galileo and Galvani and many others scientists have been forced to accept a whole series of beliefs about Nature that don't fit with common sense, but which you have to know about if you want to understand what scientists really get up to and why. I've given a list of the major ones in the book, and I hope that you have enjoyed the talk.
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