It had been growing warmer all day. When Susie looked at the thermometer at noon she wrote "82 degrees" in her little book. As they sat around the dinner table Uncle Robert asked:

"Do you find it hot in the meadow to-day?" "Rather warm," replied Mr. Leonard, "but it is fine haying weather. By night we shall have the hay in off that twenty acres, and it will be the finest crop of timothy I have had in years."

The haying had begun four days before. For a week Mr. Leonard had visited the field of timothy daily, and when he found the long heads of the graceful grass in full bloom he said:

"It is ready. We must begin to-morrow."

So the next morning the horses were hitched to the mowing machine, and Peter drove out to the meadow. The plumy heads of the tall timothy swayed on their slender stalks as they bowed before the breeze that swept over the meadow, making it look in the sunshine like the rippling surface of a quiet lake.

[Illustration: Mowing the meadow.]

It seemed a pity to cut it down, but Peter thought only of the fine hay it would make, as he drove around the meadow again and again, each time coming nearer the center.

No sound broke the stillness but the "click, click" of the sharp knives, at the touch of which the tall grass quivered a moment and then fell.

In the afternoon Donald rode the rake, to which one of the horses, strong and steady, was hitched. The horse knew his business. He needed no direction from Donald as up and down the meadow he went, with slow and even steps.

Donald sat on the small round seat, his hand grasping the lever by which he raised and lowered the long curved teeth of the rake that gathered up the hay and dropped it in long rows called windrows.

Mr. Leonard and Frank followed with their pitchforks, and piled the windrows into big round cocks. The sun shone hot and clear. A strong, dry south wind was blowing, and the air was filled with the sweet smell of the newly mown hay.

The second day Mr. Leonard rode the machine while Peter and Frank opened the hay that had been cocked the day before, so that it would be nicely dried. By noon it was all cut.

The next day they raked it up for the last time and began to stow it away in the big haymows in the barn, where the very smell of it would make the horses hungry.

"Susie and I are coming out to help this afternoon," said Uncle Robert, as, after a short rest in the cool porch, the haymakers, started for the meadow again.

"We'll take all the help we can get," replied Mr. Leonard.

"I am afraid it is going to rain," said Uncle Robert, as he started a little later with Susie for the hayfield. "The barometer has fallen since morning."

"But, uncle," said Susie, "I don't see any clouds."

[Illustration: Raking and cocking hay.]

"Watch, and you'll see them before long," returned Uncle Robert. "What is that in the west now?"

"It looks like the beginning of a cloud," said Susie.

Mr. Leonard, Peter, and Frank were loading the hay into a big wagon, while Donald raked after them.

"There's a shower coming," said Uncle Robert, pointing toward the west.

All paused and looked at the bank of clouds just coming into sight along the western horizon.

The air was still and sultry. Great beads of perspiration rolled down the faces of the haymakers.

"It's going to rain, sure," shouted Mr. Leonard, "and we must hurry or this fine hay will be spoiled. Harness up the horses to the other hayrack, Frank and Donald—be quick!"

The boys did not need urging. They felt the need, and ran to the barn.

"Bring some extra pitchforks!" shouted their father after them.

Uncle Robert pulled off his coat, and the spirit of his boyhood days came back.

Susie seized a rake and began to gather the scattered hay and pile it on the cocks.

The fresh span of horses galloped into the field. Frank brought them to a stand between two long rows of haycocks.

How they all worked! The very horses seemed to understand. They started with a jump to each new cock, and stood perfectly still as one after the other was added to their load.

"It is coming!" shouted Peter, swinging his fork to spread the great bundles of hay which came flying up to him.

The clouds looked like mountains with snowy peaks as they rose rapidly in the southwest. The mass moved under the sun and the bright silver color changed to blackness. Lightning flashes followed one another quickly. The low rumbling of thunder stirred the still air.

"It is coming!" cried Donald, as he took the reins to move to another cock. "G'long!"

All was hurry and excitement. Mrs. Leonard and Jane appeared on the scene with rakes in hand. Barri bounded from horse to horse as if that was some help.

Suddenly it grew darker. The leaves began to quiver. A curious light crept over the fields.

"There is the wind," shouted Frank. "The rain will be here in a minute."

Clouds completely covered the sky. Black forms seemed to dart out of their heavy masses.

"There's a drop," cried Susie.

Then what a wind! Straw hats were whirled away, but there was no time to run after them.

"Pile up the hay!"

The great loads staggered.

"Drive for the barn!" shouted Mr. Leonard. "Some of it must spoil, I suppose. We have done our best."

The horses moved off on the run, Frank's team ahead.

A roll and a crash of thunder followed a zigzag flash.

The hay was under cover, and the rain poured down.

[Illustration: The coming storm.]

They reached the porch just as it began to fall thick and fast. A moment more and it came down in floods, while at the same time the darkness passed away.

"How cool it is growing!" said Mrs. Leonard.

"It is twelve degrees cooler than it was at noon," said Donald, looking at the thermometer. "See, the wind has changed. It is from the northeast now."

Frank went into the dining-room, and when he came back he said, "The barometer has risen two-tenths of an inch since we looked at it last."

It seemed to rain harder than ever. The water was driven in sheets before the strong northeast wind. A stream began to run down the garden path. A vivid flash of lightning was followed quickly by a loud crash of thunder.

"That struck somewhere near," said Frank.

"I believe it was over in the wood," said Mrs. Leonard.

"See," said Uncle Robert in a few moments, pointing to a line of light in the western sky, "it is clearing already. The shower will soon be over."

The light in the west grew rapidly. The lightning became less frequent. The thunder rolled farther and farther away. The rain fell less and less heavily. The weather vane that had pointed to the northeast began to waver, and then turned toward the southwest again. It rained steadily but more gently as the clouds rolled away eastward.

And then the sun, lower now by two hours than when it was first hidden by the cloud, shone out clear and bright. Instantly everything glistened as with millions of diamonds. Even the air seemed to be filled with them, as though each raindrop was turned into a jewel as it fell.

Uncle Robert went to the front of the house and looked toward the dark cloud that was now piled up in the eastern sky.

"Come and see the rainbow!" he called.

As they looked at the bright and perfect arch that lay against the dark mass of clouds, Susie asked, "What makes rainbows, uncle?"

"It is the sun shining on the rain," replied Uncle Robert "This beautiful sunlight is made up of many, many rays. These rays fly from the sun as straight as arrows from a bow, unless something comes in their way to stop them. It seems as though such sharp little arrows of light would go right through raindrops. But they don't. They glance off the little round balls of water and bound up again like rubber balls.

"Now you know if you throw a ball straight down at your feet it bounds back into your hands. If you throw it from you, when it strikes the ground it bounds farther away. It is just so with these little arrows of light that we call rays. If the sun is high, as it is at noon, the rays are thrown back to it again. That is why we never have rainbows at noon. But when the sun is low, as it is now, instead of going back to the place they came from, they bound up against that cloud, and so make the wonderful rainbow."

"But, uncle," asked Donald, "why do we see so many colors in the rainbow? They are not in the sunlight."

"Oh, yes, they are," was the answer. "These rays of light are of the same colors that we see in the rainbow. It takes all of them mixed together to make the clear white light which we call sunlight, and without which nothing could live or grow.

"As the raindrops throw them up against that cloud, they are separated again, because some colors are more easily bent than others. The red, you see, is the highest and the violet the lowest in the bow. The raindrops make a prism. You have seen a prism. But through the prism the colors are turned the other way; the red is lowest and the violet highest."

"How fast the rainbow is fading away!" said Susie. "I wish it would stay."

"The rain is over," announced Donald, leaving them and walking out toward the garden. "The sky is quite clear."

"It is getting warm again," said Frank, looking at the thermometer, "but it does not feel hot as it did before the rain."

"The barometer is just where it was this morning," said Susie, coming from the dining-room.

"It is drying off very fast," said Uncle Robert. "Let us walk out and see how the garden stood its drenching."

"Put on your rubbers, Susie," called Mrs. Leonard from the house.

As they crossed the yard they passed a pan in the bottom of which the water stood an inch or more deep.

"That shows how much rain fell," said Uncle Robert, pointing to the pan.

"Do you mean if it had stayed on the ground where it fell it would have been that deep all over?" asked Susie. "Would that have been very much?"

"I think it would," was the smiling reply. "You might try to find out how much fell on the garden alone if it was an inch deep all over."

Susie shook her head.

"I don't know how," she said.

"Uncle," said Frank, "in the weather reports they always tell how much rain falls, even if it is only a small part of an inch. How can they tell when it is so little?"

"They have what is called a rain gauge, by which a very small amount of rainfall can be measured. By the way, we might have a rain-gauge of our own. It would be easy to make one with the help of a tinsmith. Is there a tinsmith in the village?"

"Yes," answered Frank, "but I don't believe he has much to do."

"So much the better for us," laughed Uncle Robert. "Susie, while these other people are busy tomorrow, shall we drive to the village and see if we can get the tinsmith to help us make a rain-gauge? I have a little book somewhere that tells just how it should be done."

Susie was delighted at the thought of such a day with Uncle Robert, and the boys were so interested in the prospect of having a rain-gauge of their own that they could hardly wait for to-morrow to come.