The first one goes up before anybody is ready. There is always a family still walking down from the truck with a cooler, always a kid who has just been told to stay on the blanket, and then the thump comes across the water and every head turns. A red line climbs. It hangs. It opens. And for about four seconds the whole crowd, a few thousand people who came out to wherever the town gathers to watch on the Fourth, is looking up at the same thing with the same face.
That is Independence Day at the bay, and it deserves a whole essay before the turn, because what is happening up there is a series of chemical reactions running in a specific order, timed to the second, inside a cardboard shell that somebody packed by hand, and knowing that makes it better, not worse.
The thump is a lift charge. The shell sits in a mortar tube, a length of pipe stood on end, and under it is a bag of black powder. Black powder is the oldest explosive there is: charcoal, sulfur and potassium nitrate, ground together, worked out in China somewhere around a thousand years ago by people who by most accounts were looking for a medicine and found this instead. Light it and the nitrate gives up its oxygen fast, the charcoal and sulfur burn in that oxygen faster than anything can burn in open air, and the gas that results has nowhere to go but up. The shell leaves the tube at a couple of hundred miles an hour. On its way out it lights a time fuse.
Then it climbs, silent, for a few seconds. That is the fuse burning. The people who make shells cut the fuse to the height they want, so the shell breaks at the top of its arc, when it has stopped rising and has not yet begun to fall. That pause is the whole art. Too short and it bursts low and hurts the ears. Too long and it opens on the way down, ragged and sad. At the top, the fuse reaches the burst charge, more powder packed at the center, and the shell blows open, and what it throws outward are the stars.
Stars are the point. A star is a pellet about the size of a marble or a sugar cube, and it is a recipe. It needs a fuel, something to burn. It needs an oxidizer, because at that speed there is no time to wait for the air; usually a perchlorate or a nitrate, salts that hold three or four oxygen atoms tightly to each chlorine or nitrogen until they are hot and then let them all go at once. A binder holds the whole thing together. And then there is the color.
The color is the part everyone asks about, and the answer is that fireworks are a flame test on a very large scale. Any high-school chemistry room has done it: dip a wire in a salt, hold it in a flame, watch the flame change. The heat throws the electrons in the metal atoms up to higher energy levels. They cannot stay there. They fall back, and as they fall they give off the difference as light, and the difference is different for each element, so each element has its own color. Strontium gives red. Barium gives green. Sodium gives yellow, the same yellow as the old streetlights, which were nothing but sodium vapor made to glow. Copper gives blue. Mix strontium and copper and you get purple. Add magnesium or aluminum powder and you get white, and sparks, and the brightness that makes the whole shell look like it is burning hotter than it is. The colors are fingerprints. An astronomer reads the same fingerprints in the light of a star a thousand light-years off, and knows what it is made of without going there. The kid on the blanket, watching a red one open, is reading strontium the same way.
Blue is the hardest. Everyone who makes fireworks will tell you that. The copper compound that gives the good deep blue falls apart if the star burns too hot, and goes dim if it burns too cool, and the window between is narrow. A show with a real blue in it, not a washed-out lavender but a true blue, is a show made by someone who knows what they are doing. Watch for it. It is rarer than you think.
The shapes have names, like roses. A peony is stars that fly straight out and burn clean. A chrysanthemum leaves trails. A willow hangs in the air and droops, because the stars are made to burn long and fall slow. The crackling ones are tiny pellets of a different composition that pop one after another as they burn through. The ones that whistle are a tube with a fuel that burns in pulses, and the pulses happen to fall in the range of the human ear. All of it is chemistry doing what it does when you arrange the right atoms next to each other and add heat.
A firework is also, if you follow it backward, the least independent thing there is. The strontium was dug out of the ground somewhere and refined somewhere else. The aluminum powder took an enormous amount of electricity to make, more per pound than almost any other common metal. The perchlorate is an industrial chemical with a supply chain behind it. The paper is trees. The glue is chemistry. The plastic fuse cover, the plastic wrapping, the cardboard, the ink on the label: nothing in that shell came from one place, and nearly all of the shells lit in this country on the Fourth were packed on the other side of the world and shipped here in containers. Every burst over the bay is a small map of the planet, opening up and falling back down into the water.
Which is a funny thing to celebrate independence with, until you think about it, and then it is exactly right.
The nation that was declared that July was not declaring that it would go it alone. It was declaring that it would decide for itself, which is a different thing. From the first day it traded; it had to, it was a coast with a lot of harbors, and the more independent it became the more it depended on everyone else. There is no contradiction in that; it is what freedom looks like once it has grown up. A free person still needs things. What is different is that the obligations are chosen.
This town is one of the places where the country's obligations are manufactured. The ships come up the channel with crude from wherever crude is coming from that week. The plants take it apart. What goes back down the channel, or out by rail and pipe, is fuel for the planes and cars, and the beginning of every plastic thing in every hospital and grocery store and toy aisle in the country, and a good share of what the country sells abroad. The complex at the edge of town on the channel is one of the largest of its kind in the nation, and the nation's independence, its ability to move, to build, to feed and cool and light itself, is made of interdependence, and a great deal of that interdependence passes through here. A country does not run on a flag. It runs on a channel.
There is an older independence a few miles up that channel, too. Across the water at San Jacinto, Texas won itself from Mexico in about eighteen minutes on an April afternoon in 1836, and the monument that stands there is taller than the one in Washington. That fight was also fought with black powder, charcoal and sulfur and nitrate, the same recipe that is lifting the shells tonight. The chemistry has not changed in a thousand years; what changed is what people do in the quiet after the smoke clears.
Consider the operator on the tower tonight, because somebody is up there. The plant does not stop for the Fourth. From the top of a unit you can see shows going off in every direction, the town's, the neighbors', the little ones in backyards that are technically not allowed, and you can see the flare beside you, which is the same thing in a way: a controlled burn, a fuel and an oxidizer, light given off by atoms dropping back to where they belong. The difference between a firework and a flare is intention and audience. One burns to be seen. The other burns so that something worse doesn't happen. Both are a nation's chemistry, held in a pipe by somebody paying attention.
The atoms in every star that opens tonight were made in actual stars, a long time ago. Strontium and barium were cooked up mostly in the slow last age of ordinary stars, swollen and shedding; copper came partly from those and partly from the explosions of bigger ones. All of it was thrown out into space and eventually gathered into a planet and eventually dug up and eventually packed into a paper shell by a person at a bench. When the shell opens, those atoms glow at the colors that belong to them and to nothing else, the same colors that told the astronomers where they came from. That is where the red comes from.
The last shell is always the biggest, and then there is a pause, and then the applause, thin across the water, and then the sound of a few thousand people finding their keys. The smoke drifts. It goes the way the wind goes, which on a July night here is usually off the Gulf and inland, so it moves over the town and thins and is gone. Somewhere in the grass along the shore, in the dark, the last of the cardboard comes down, scorched at the edges, light as a leaf, with the name of a factory on the other side of the world still printed on it.