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.
[Illustration: A RETORT.]
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.
[Illustration: KITTY IN THE GAS-WORKS.]
"As soon as the gas gets through the purifiers," said he, "it comes, by
an iron pipe, in here, and is made to pass through and give an account of
itself before any of it is used. And now I suppose you would like to know
how it does report its own amount, wouldn't you?"
[Illustration: THE METRE.]
Philip and Kitty both were sure they did want to know, so he sketched a
little plan of the metre on a piece of paper, and then went on to explain
it:
"This shows how the metre would look if you could cut it through in the
middle. The large drum-shaped box A. A. is hollow, and filled a little
more than half way up with water. Inside it is a smaller hollow drum, B.
B. so arranged as to turn easily from right to left, on the horizontal
axis C. This axis is a hollow pipe by which the gas comes from the
purifiers to enter the several chambers of the metre in turn, through
small openings called valves. The partitions P. P. P. P. divide the drum
B. B. into--let us say--four chambers, 1, 2, 3, 4, all of the same size,
and capable of holding a certain known amount of air or gas. The chamber
1 is now filled with gas, 3 with water, and 2 and 4 partly with gas and
partly with water. The valves in the pipe C are so arranged that the gas
will next pour into the chamber 2. This it does with such force as to
completely fill it, lifting it quite out of the water and into the place
that 1 had occupied before. Then as 1 is driven over to the place which 4
had occupied, the gas with which it was filled passes out by another pipe
and off to the large reservoir you will see by and by, its place being
filled with water. At the same time 4 is driven around to the place of 3,
and 3 to that of 2. The water always keeps the same level, and simply
waits for the chambers to come round and down to be filled.
"Next, 3, being in the place of 2, receives its charge of gas from the
entrance pipe, is in turn lifted up into the central position, and sends
all the other chambers around one step further. And when the drum gets
completely around once, so that the chambers stand in the same places as
at first, you know each chamber must have been once filled with gas and
then emptied of it. If then we know that each chamber will hold, say two
and a half cubic feet of gas, we are sure that every time the drum has
turned fully around it has received and sent off four times two and a
half feet, or ten feet in all. Now we connect the axis C with a train of
wheel-work, something like that in a clock, and this wheel-work moves the
pointers on the dials in front, so that as the gas in passing in and out
of the chambers turns the drum on the axis, it turns the dial pointers
also.
"The right hand dial marks up to one hundred. While its pointer is
passing completely around once, the pointer on the next dial (which marks
up to one thousand) is moving a short space and preserving the record of
that one hundred; and then the first pointer begins over again. The two
pointers act together just like the minute and hour hands on a clock.
Then the next dial marks up to ten thousand, and acts in turn like an
hour-hand to the thousands' dial as a minute-hand, and so on. You see
each dial has its denominations, 'thousands,' 'hundred thousands,' or
whatever it may be, printed plainly below it. And now, when we want to
read off the dials, we begin at the left, taking in each case the last
number a pointer _has passed_, and read towards the right, just as you
have learned to do with any numbers in your 'Eaton's Arithmetic.' There
is one thing more to remember, however; the number you read means not
simply so many cubic feet of gas but so many hundred cubic feet."
Philip and Kitty immediately set to work to read the dials on the office
metre, and found that they were not now so very mysterious.
"But how do you know how much people use?" asked Philip. "There is
something like this metre, only smaller, down cellar at home, and a man
came and looked at it the other day, to see how much gas had been burned
in the house he said, when I asked him what he was going to do."
"The metre you have at home works in the same way as this," said Mr.
Carter, "and the dial-plates are read in the same way. But the gas that
your little metre registers is only that which you take from the main
supply-pipe, to light your parlors and bed-rooms.
"When a stream of gas from the main enters the house, it has to pass
through the metre the very first thing, before any of it is used; and
each little metre keeps as strict an account of what passes through from
the main to the burners, as the large one here in the office does of that
which passes from the purifiers to the reservoir. But there is this
difference between the two: the gas keeps pouring through the office
metre as long as we keep making it in the retorts, but it passes through
your metre at home only just as long as you keep drawing it off at the
burners. So if we find by looking at the metre that 5450 feet have passed
through during a given time, we send in our bill to your papa for that
amount, knowing it must have been burned in the house.
"But most likely the metre doesn't say anything directly about 5450. It
says, perhaps, 11025. 'How can that be?' you would think. 'We haven't
burned so much as that,' and you haven't--during this one quarter. But
after the metre had been inspected at the end of the last quarter, the
pointers did not go back to the beginning of the dials and start anew;
they kept right on from the place where they were, so that 11025 is the
amount you paid for last time and the amount you want to pay for this
time, lumped together. Now this is what we do. We turn to our books and
see how much you were charged with last time, and subtracting that record
from the present record leaves the amount you have used since the last
time of payment.
"Then suppose another case. Your metre registers only as far as 100,000.
At the end of the last quarter it marked 97850; now it records but 3175.
How would you explain that, master Philip?"
Philip looked puzzled a moment, and then said,
"I should think it must have finished out the hundred thousand and begun
over again."
"Exactly. And to find the amount for this quarter you would add together
the remainder of the hundred thousand (2150) and the 3175, and get 5325,
the real record. But I guess you've had arithmetic enough for the
present, so we'll go out now and see the gasometer, or gas reservoir."
They all went out of doors then, papa, Mr. Carter, Philip and Kitty,
across a narrow court-yard. There was a huge, round box, or drum, with
sides as high as those of the carriage-house at home, but with no opening
anywhere, "like a great giant's bandbox," thought Kitty. Four stout
posts, much taller still than the "bandbox" itself, were set at equal
distances around it, and their extremities were joined by stout beams
which passed across over the top of the gasometer.
As the children went up nearer to it, they saw it was made of great
plates of iron firmly riveted together, and that it did not rest on the
ground, as they had supposed, but in the middle of a circular tank of
water.
"After the gas has been made and purified and measured," said Mr. Carter,
"it is brought by underground pipes into this gasometer, and from here
drawn off by other pipes into the houses. The weight of this iron shell
bearing down upon the gas, gives pressure or force enough to drive the
gas anywhere we wish."
[Illustration: THE GASOMETRE.]
"But why do you put the--the iron thing in water, instead of on the
ground?" asked Kitty.
"So as to make it air-tight, and give it a chance to move freely up and
down. Of course if the iron shell were empty its own weight would make it
sink directly to the bottom of the water-tank and stay there. But gas,
you know, is so much lighter than common air that it always makes a very
strong effort to rise higher and higher, carrying along whatever encloses
it. You saw that illustrated in the balloon that went up last Fourth of
July. Now, as the gas from the works pours into the reservoir from
beneath, it is strong enough to lift the iron box up a little in the
water. Of course that gives a little more room. Then as more gas comes in
to take up this room, the gasometer keeps on rising slowly. We make sure
of its not rising above the water and letting the gas leak out, by means
of the beams you see stretched across above it. They are all ready to
hold it down in a safe position if the need should come.
"On the other hand, as the people in town draw off the gas to burn, the
gasometer would, of course, tend to sink down gradually. So we have the
water-tanks made deep enough to allow for every possible necessity in
that direction. In very cold weather we keep the water from freezing by
passing a current of hot steam into it. If it should ever freeze, the
gasometer might as well be on the ground, for it could not move up and
down, or be trusted to keep the gas from leaking out around the edges.
With these precautions, however, we know it is perfectly trustworthy."
"I saw it one morning early, when I was out coasting on the hill," said
Philip, "and it wasn't more than half as high as it is now."
"A great deal had been drawn off during the night and we had not been
making any more during the time to take its place."
"Does it ever get burned out too much?"
"No, there's no danger of it. We make enough to allow a good large margin
above what we expect will be used."
The children looked about a little longer, and then, with good-byes and
many thanks to Mr. Carter, walked home again with papa, over the crisp,
hard snow.
Next week Philip had a composition to write at school. He took "Gas" for
his subject, and wrote:
"Gas that you burn is made out of soft coal. They put it in Ovens
and cook it until it is not coal any longer. The Ovens are so hot
you cant go anywhare near them but the men do With poles and big
lether aprons. I would not like to shovle in the coal. I would
rather have a Balloon. They use two or three tons every day. it
makes coke and Tar and the gas that goes up the pipes. They make
the gas clean and mesure it in a big box of water, and tell how
much there is by looking at the clock faces in front. Then it goes
into a big round box made of iron and then we burn it. but I do not
like to smell of it. you must not blow it out for if you do you
will get choked. This is all I Remember about gas.
"PHILIP RAYMOND LAWRENCE."