wheels. You go to the wheels. You see no Force there, but a stranger; but if it is the giant Force that you have lost from the engine, this stranger will be a giant; if Force is at his pigmy tricks, the stranger will be a dwarf; and, in either case, he will tell you his name is Heat. While you are staring at him, you observe something familiar about him, and you say, 'Pray, Mr. Heat, have I not seen you before somewhere about the engine? You are the fireman, perhaps!' 'Exactly,' answers Heat. 'I was in the fire under the boiler.' Under the boiler! Why, that is where our lost Force came from. Put it all together. You put heat under the boiler, and force comes out and pulls the train. You miss Force, and, when you go to look for him, you find Heat in his place. Is it not reasonable, good Mr. Traveler, to think that, as Heat can turn into Force, Force can turn back into Heat again?"

"Your royal highness," cried the little traveler, jumping up in a great rage, “I hope your royal highness won't listen to such stuff as this. Heat a person, indeed! Heat is a fluid, and it is called caloric. I see my Lord High Fiddlestick is laughing, but he won't laugh long. Here is the dictionary, and the word in it to prove what I say; and the ungreased wheels were hot because they turned so hard that some of their caloric was squeezed out of them; and when the hammer came down hard on the iron, some of the caloric was squeezed out of that, and all the old philosophers say so; and, if you want us to believe that force is not burned in the fire, and blown off from the engine, and crushed under the wheels, but is turned into heat, you must make us swallow the dictionary and the old philosophers first."

"I see I must tell you a little story," answered my Lord High Fiddlestick, gently. "As my friend Count Rumford and your friend Force were one day boring a cannon, Count Rumford tried to pick up some of the brass chips that Force had just cut off, and discovered that they were hotter than boiling water. Brass is not generally hotter than boiling water. Before we go farther, perhaps you will tell us, Mr. Traveler, what had happened to these chips."

"Why, the boring had squeezed so much caloric fluid into these chips," answered the traveler.

"Then, of course," said my Lord High Fiddlestick, "if the brass chips held so much more heat-fluid than they ever held before, they must be altered in some way. If you were going to put say a quart of heat-fluid in chips that only held a pint before, you must alter your chips. But Count Rumford found that the chips were not altered; that is, if you are right, Mr. Traveler, a pint could hold a quart; and he thought that was tougher to swallow than the old philosophers. So he took a hollow tube of brass called a cylinder. In it he put a flat piece of hard steel. The steel was almost as large as the cylinder, so that it could just turn around the steel. He put the cylinder in a box filled with water. A horse was made to turn the cylinder round and round. The piece of steel rubbed hard all the time on the bottom of the brass cylinder. The brass grew warm and the water grew warm. Count Rumford and a great many people stood watching it curiously. The cylinder turned and turned, all the time growing hotter. The water all the time grew hotter too; and, at the end of two hours and a half, the water was so hot that it boiled. Now, Mr. Traveler, what makes water boil ?”

"Heat," answered the little man, sulkily.

"Well, there was no heat here," cried my Lord High Fiddlestick 66 only force; and force made the water boil. Own up, Mr. Traveler. It begins to look as if Heat and Force were the same person.'

"I shall not own any thing of the sort," answered the little man. "Pray, my Lord High Fiddlestick," catching up the hammer and bringing it down hard on the iron, “how did force turn into heat then?"

"This iron," said my lord, "is made of what we call atoms-tiny particles too small to be seen separately." "Bosh!" snorted the traveler.

"These atoms," said the Lord High Fiddlestick, "are held fast together by a liking they have for each other an attraction that we call cohesion. Force strikes this iron with the weight of the hammer. He jars the iron; he jars, he

stirs the atoms; they can stir, although their band of cohesion holds them so close that they look as if they were stuck tight together. The hammer is down. You would say Force is dead. I say he has gone in among those atoms; he is carrying on the stir and jar from one atom to the other. 'Stop!' says Cohesion, trying to hold them fast. 'Go on!' cries Force. The atoms of iron can not get away from one another, but they can move. Force makes them move and struggle. When you struggle you get warm. When the atoms of iron struggle, they make what my friend, Lord Bacon, calls the fire and fury of heat. They actually get farther away from each other; and this is why philosophers will tell you that heat makes a body larger.

"This hard, solid iron is actually a little larger than when it was cool, because the atoms have succeeded in getting farther from each other. Now all the king's horses, and all the king's men, if you could set them to tug on each side of this little bit of iron, have not strength to do that. It required a great force, stronger than all the king's horses and men. But who did pull the atoms? Heat. Then heat is force, or perhaps I should say motion; for, when we struck this iron with the hammer, and it became warmer, what had happened really? Why, the motion of the arm and hammer that struck it went in among the atoms of iron, and they moved and pulled a little way from each other. really their motion; and so-"

What we call Heat was

"When a man comes

"Stuff!" interrupted the traveler. down to atoms, he must be hard up for proofs."

"Comes down to atoms!" exclaimed my Lord High Fiddlestick, opening a window. Outside, the sill was covered with fresh-fallen snow, which my Lord High Fiddlestick scraped up in his hands. "Can any thing be softer than this snow?" he asked. "Well, the pull and strain that brought the water-atoms together to make such snow as I hold here, would pitch a ton of stone over a precipice two thousand feet deep. Come down to atoms, indeed! Pray, let me show you a few of the things that atoms can do." "My lord," interrupted the king, in a hurry, "I observe that dinner is ready, and the beefsteak on the table. If the

steak gets cold, according to your philosophy, it will grow smaller, and then, perhaps, there will not be enough to go round. Let us go to dinner, and hear what the atoms can do another time, my Lord High Fiddlestick.”

BIRDS AND THEIR WAYS.—From the Little Corporal. About the second week of March, here in Northern Illinois, I hear somebody singing up in the air, "Ka-wet! kawet!" His back is as blue as the violets, and his breast looks as red and warm as a little red cloud at sunrise.

The trees are bare, the grass is dry, and Bluebird's voice is a little sad at first, but by the middle of April he is all over it, for he takes him a mate; then he is very busy trying to find a place for the nest that is to hold the wee ones.

One day I saw a pair of bluebirds sitting on the stakes of a rail fence. Bluebird flew down to a hole in one of the rails; he went in, examined its sides with his black bill, turned around in it, then, flying up to the top of a stake, warbled "Ka-wet! que-we-o-it!"-my dear, come look at it. Mrs. Bluebird answered "Ka-wet !"-yes, dear. They examined and consulted a long time, but it would not do to put their nest there; the room was too small, and the roof very poor. I saw them there no more. The mates sometimes choose a hole in a tree, where a busy woodpecker once made his nest. They carry in grass, wool, and feathers, and arrange a soft, warm nest. The female lays from four to six pale blue eggs. Two broods a year are raised. Bluebirds live upon worms, beetles, and other insects that would destroy our fruit and gardens.

Generally, within two weeks from the time I first hear the plaintive salutation of the bluebird, a chorus of spring voices are in my ear. The red-winged blackbirds are chatting in the tree-tops; the crow blackbird throws in an occasional note of reproof; the meadow-lark sings "E-chee-a-chirp-pa" in the richest of voices; the snowbird trills in the hazel bush; the wild ducks are quacking on the streams; the soft piping of the nuthatch sounds from the woods; the belted kingfisher darts chattering by, and the plover flies over, crying sharply "Kill-deer! kill-deer!"

But whose voice is this I hear a few days before the coming of April? He calls from the trees, just at evening, "Quit! quit! quit !" The night is cold and frosty, but with the early morning light a rich bugle-voice breaks out in "Ka-i-a ka-e-ore quit! cho-wo que-we que-wit! tka-a-ru kawe-wa ka-we-wa tkeep!" Robin knows how to sing. I once heard four singing in one bur-oak at a time.

Look at Robin when he is on the ground. He gives a hop or two, then runs a few feet straight forward in a very, careless way. He stops, turning one eye up as if he needed to keep watch of the weather, while with the other he looks sharply at the ground. Now he finds a bug or grub, now a May-beetle, and a little farther on he pulls up a cut-worm. He is very useful, for he eats up some of the worst enemies of the fruit and grain.

The first day of last May, as I passed a thorn-tree, a bright eye peered from behind a branch. A moment after, two brown wings were spread, and away went Mrs. Robin. Robin himself sat near by, on a crab-apple-tree, jerking his tail, and eying me anxiously. Here was a nest with four blue eggs.

Soon the bluejays became too inquisitive, and I often saw Robin dart out bravely and drive them off. After a few days I found the nest deserted, one egg gone, and the rest cold. I am afraid Bluejay took that egg.

But the robins were not discouraged. They built another nest on the branch of a bur-oak a short distance from the first nest. They left this one also, and without using it at all.

A third nest was made in a black oak, whose boughs touch our house. Mrs. Robin constructed it chiefly of dried grass, and plastered the inside with mud. When the mud was dry, she lined it smoothly with fine soft grass, and the nest was ready for use.

The eggs were laid, and for about two weeks patient Mrs. Robin kept them warm under her red breast. The sweet June days came, and the wild roses showed their bright buds. Robin, meantime, sang his richest songs on the boughs near by. He became almost as tame as a chicken,

L