Philip and Kitty were curled up together on the lounge in the library, reading Aldrich’s “Story of a Bad Boy.” It was fast growing dark in the corner where they were, for the sun had gone down some time before, but they were all absorbed in Tom Bailey’s theatricals, and did not notice how heavy the shadows were getting around them. Papa came in by-and-by.

“Why, little folks, you’ll spoil your eyes reading here; I’d better light the gas for you,” and he took out a match from the box on the mantle.

“O, let me, please,” cried Philip, jumping up and running to the burner. So he took the match, and climbed up in a chair with it. Scr-a-tch! and the new-lit jet gave a glorified glare that illuminated everything in the room, from the Japanese vase on the corner bracket to the pattern of the rug before the open fire. But as Philip turned it off a little it grew quieter, and finally settled down into a steady, respectable flame. Philip always begged to light the gas. It had not been long introduced in the little town where he lived, and the children thought it a very fine thing to have it brought into the house, and secretly pitied the boys and girls whose fathers had only kerosene lamps.

“Why can’t you blow out gas, just as you do a kerosene light?” asked Kitty, presently, leaving the Bad Boy on the lounge, and watching the bright little crescent under the glass shade.

“Because,” explained papa, “unless you shut it off by turning the little screw in the pipe, the gas will keep pouring out into the room all the time, and if it isn’t disposed of by being burned up, it will mix with the air and make it poisonous to breathe. A man at the hotel here, a few nights ago, blew out the gas because he did not know any better, and was almost suffocated before he realized the trouble and opened his window.”

“And where does the gas come from in the first place?” pursued Kitty.

“Why, from the gas-works, of course,” said Philip in a very superior way, for he was a year the elder of the two. “That brick building over by Miller’s Hill—don’t you know—that we pass in going to Aunt Hester’s.”

“I know that as well as you do, Philip Lawrence,” said Kitty with some dignity. “What I wanted to know was what it’s made out of. What is it, papa?”

“Out of coal,” said papa. “They put the coal in ovens and heat it till the gas it contains is separated from the other parts of the coal, and driven off by itself. Then it is purified and made ready for use.”

“Out of coal? How funny! I wish I could see all about it,” said Philip, looking more interested.

“And so do I wish I could,” added Kitty.

“I don’t see why it cannot be done,” said papa. “If you really care to see it, and won’t mind a few bad smells, I will ask Mr. Carter to-morrow morning, when he can take you around and explain things.”

The next day when Mr. Carter was asked about it, he said, “O, come in any day you like. About three in the afternoon would be a good time, because we are always newly-filling the retorts then.” This sounded very nice and imposing to the children, and at three the next afternoon they started out with papa. The gas-house certainly did smell very badly as they drew near it, and dainty Kitty sniffed in considerable disgust. Philip suggested that perhaps she had better not go in after all; he didn’t believe girls ever did go into such places. And upon that Kitty valiantly declared she did not mind it a bit, and sternly set her face straight.

Mr. Carter met them at the door. “You are just in time to see the retorts opened,” said he, and led the way directly into a large and very dingy room, along one side of which was built out a sort of huge iron cupboard with several little iron doors. The upper ones were closed tight, but some of the lower ones were open a crack, and a very bright fire could be seen inside. Everything around was dirty and gloomy, and these gleams of fire from the little iron doors made the place look weird and ghostly. Long iron pipes reached from each of the upper doors up to one very large horizontal pipe or cylinder near the ceiling overhead. This cylinder ran the whole length of the room, and, at its farther end, joined another iron pipe which passed through the wall.

“Those are the furnace-doors down below,” said Mr. Carter to the children. “What you see burning inside of them is coke. Coke is what is left of the coal after we have taken the gas and tar out of it. The upper doors open into the retorts, or ovens, that we fill every five hours with the coal from which we want to get gas. Each retort holds about two hundred pounds, and from that amount we get a thousand cubic feet of gas.”

“Is it just common coal;” asked Kitty, “like what people burn in stoves?”

“Not exactly. It is a softer kind, containing more of a substance called hydrogen than the sorts that are generally used for fuel. Several different varieties are used: ‘cherry,’ ‘cannel,’ ‘splint,’ and so on, and they come from mines in different parts of England and Scotland, chiefly. Glasgow, Coventry and Newcastle send us a great deal.”

Philip started as if a bright idea had struck him. “Is that what people mean when you’re doing something there’s no need of, and they say ‘you’re carrying coals to Newcastle?’”

“Yes. You see such an enterprise would be absurd. Just notice the man yonder with the long iron rod! He is going to open one of the retorts, take out the old coal—only it is now coke—and put in a fresh supply.”

A workman in a grimy, leather apron loosened one of the retort doors, and held up a little torch. Immediately a great sheet of flame burst out, and then disappeared.

He took the door quite off, and there was a long, narrow oven with an arched top, containing a huge bed of red-hot coals.

“What a splendid place to pop corn!” exclaimed Kitty.

Papa laughed. “You would find it warm work,” said he, “unless you’d a very long handle to your corn-popper.” And Kitty thought so too, as she went nearer the fiery furnace.

“You see,” said Mr. Carter, “these red-hot coals have been changed a great deal by the heat. They have given up all their gas and tar, and are themselves no longer coal, but coke. We shovel out this coke and use it as fuel in the furnaces down below to help heat up the next lot. Then new coal is put into the retorts, and they are closed up with iron plates, like that one lying ready on the ground.”

“It’s all muddy ’round the edge,” observed Kitty.

“Yes, that paste of clay is to make it air-tight. The heat hardens the clay very quickly, so all the little cracks around the edge are plastered up. When the coal is shut up in the ovens, or retorts, the heat, as I just told you, divides it up into the different substances of which it is made; that is, into the coke which you have seen, a black, sticky liquid called tar, the illuminating gas, and more or less ammonia, sulphur, and other things that must be got rid of. Almost all these things are saved and used for one purpose or another, though they may be of no use to us here. If we have more coke than we ourselves need it is sold for fuel. The coal-tar goes for roofing and making sidewalks, or sometimes (though you wouldn’t think it possible, as you look at the sticky, bad-smelling, black stuff) in the manufacture of the most lovely dyes, like that which colored Miss Kitty’s pink ribbon. The ammonia is used for medicine and all sorts of scientific preparations, in bleaching cloth, and in the printing of calicoes and cambrics.”

“When the materials of the coal are separated as I told you in the retorts, most of the tar remains behind, and is drawn off; but some gets up the pipes. That large, horizontal cylinder is always nearly half full of it. The gas, which is very light, you know, rises through the upper pipes leading from the retorts, and bubbles up through the tar in the bottom of the cylinder. Then it passes along the farther end of the cylinder, and into the condensing pipes.”

He opened a door, and they went through into the next room. Here the large pipe which came through the wall of the room they had just left, led to a number of clusters of smaller pipes that were jointed and doubled back and forth upon each other, cob-house fashion.

“When the gas goes through these pipes,” said Mr. Carter, “it gets pretty well cooled down, for the pipes are kept cold by having so great an amount of surface exposed to draughts of air around them. And when the gas is cooled the impurities are cooled too, so that many of them take a liquid form and can be drawn off.”

The next room they entered had a row of great, square chests on each side, as they walked through.

“These are the purifiers,” explained Mr. Carter again. “They are boxes with a great many fan-like shelves inside, projecting out in all directions, and covered thickly with a paste made of lime.”

“Lime like what the masons used when they plastered the new kitchen?” asked Philip.

“About the same thing. The boxes are made air-tight, and the gas enters the first box at one of the lower corners. Then before it can get through the connecting-pipe into the next box, it has to wind its way around among these plates coated with lime. This lime takes up the sulphur and other things that we do not want in the gas, and so by the time it gets through all the boxes it is quite pure and fit to use.”

Then the party all went into the room where the gas was measured. It was a little office with a queer piece of furniture in it; something that looked like a very large drum-shaped clock, with several different dials or faces. This, Mr. Carter said, was the metre or measurer, and by looking at the dials it could be told exactly how much gas was being made every day.

KITTY IN THE GAS-WORKS.