The following is some part concerned with scientific Fourcroy, chosen from a " discovery" programm 
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This is the brightest light in history so far, caused by electricity arching across between these two carbon rods and causes them to burn incandescene(白热光), keeping the rods in right distant apart as they are burning away is something a French called Fourcroy thinks out. He called it a regulator, and basically it uses a tiny variation in current as the rods burnt away, to run a clock mechanism that moves the rods around keeping them close together. In the theater, the arc light is an art to every actor’s prayer. In the meanwhile, Fourcroy had other more heavenly ideas.
The other thing Fourcroy does can only be described as cosmic. The first proper experimental version of it happens here in the Pampelune(伟人祠)in the center of Paris. And it is one of those scientist discoveries that gives you goose bumps. Fourcroy takes a heavy ball and attached it to a great long wire and make sure that wire isn’t twisted. Then he put it off to one side and fixed it to the wall with a piece of string. And then to make sure nothing will influence to the swing of the ball in a slightest way. He burnt the string, the string burnt through, snaps and the ball started to swing.
Now here is a bit above all mind , if we move our camera, so it stays in line with this ball, and we used a time-line photography and I stay as still as I can, you will see what Fourcroy saw. The ball goes on swing in the same place in a natural space, independent of the earth. What you are seeing now is extraordinary. It is what you see if you are watching the earth from somewhere in outer space. In 1851, when Fourcroy does this, he finally proves that Copernicus was right. The earth does rotate. Watch it again, you what the meaning about goose bumps. It is the earth turning. I said it was a cosmic idea, because if we put Fourcroy’s clock arch light regulator together with his inertial pendulum(惯性摆锤), this only is one thing you can use them for , to save scientists from eye strain.
Put yourself in an astronomist place, staring up at a nightly show, within by, because thanks to the fact the earth spin a thousands miles an hour, you will have to move in a fair leg, and the stars aren’t. look at the stars through a fixed telescope. And what you see is, there it was gone. Fourcroy is doing that inertial pendulum and realizes the trick to the star-gazing is to use a clock-work regulator, remember the arc light to turn the telescope the opposite way to the earth. So heavenly bodies staying in the frame, just long enough for Fourcroy to do what he does next, take photograph in 1845. He gets the 1st clear shot of the sun, and then, 6 years later, this, the solar corona, these things here, called prominence(日珥)which people always thought were optical illusions. Fourcroy’s photo shows that they are real and then the 1st clear detail of these sun spots, which turned out not to be mountains.
En, where are we? I mean the story. Electric crystals help Pierre and Marie Currie discover what they called radium(镭), and then Langevin used the crystal to develop sonar that help save Liberty ships, put together with welding techniques, using a settling mate of carbon rods, also working in arch lights, with clock regulator built by Fourcroy, whose inertial pendulum helps to take photo of solar eclipse. And astronomy really takes off. Look, with tracking telescope you take precise in our photographs to spot about the smallest changes between one photograph and the other, you overlaid the pictures and it is easy to see what you just missed. Watch this spot again, see? And then you can overexpose this photograph and even the very faint stars became visible and you can really start to enjoy the wonderful nightly show up there.
And speaking of the shows, that’s where Fourcroy gets his photography from in the 1st place. Ok, this is 1822 version of virtual reality, called a “ diorama”, and the excitement of Paris Elite sociate. Now bottom left is the view of the audience gets. It was brought to scene behind a closet setting, we know, as a giant gauze panel, and lighten it to put a phoney effect on everything. Put a light on scene itself and off the phony gauze and the scene clears. Take light off the spring scene, and onto the snow scene behind, and what you will see, a painted gauze scene, and show it up because it is lightened, or doesn’t, because it’s not. Boring, right? Wrong. Back then for the locals, this is buffer crazy extravagant Hollywood stuff.
