Mary and her mother lay on a bunk and beyond the partition one could hear the even breathing of father and cousin Jack. All else was still save the occasional cry of a night hawk or the far distant call of a coyote.

Slowly, cautiously, stealthily into this silence crept a tiny object. Its sharp, black eyes flashed fire in the moonlight and in its small mouth it carefully carried a cactus burr.

"Pst! Mary, did you hear something?" It was cousin Jack's hoarse whisper that broke the silence and awakened Mary from a beautiful dream and her eyes popped open wide. She snuggled closer to Mother and stared into the moonlight. All she could hear was a funny, little scratching sound, unlike any she had ever heard around camp, and she knew not what it meant. None of her little animal friends made a noise like that.

Jack was out of bed, had lighted a candle and in his pajamas, was searching under bunks, tables and chairs for the thing that had caused the noise. Mary sat up in bed, in time to hear a swift, rustling sound and see a small object dart out of the tent door. Jack knew it would do no good to search outside so tumbled back into bed and once more all was still.

Next morning at breakfast all were wondering who the strange visitor could have been, but soon the incident was forgotten. Toward noon, Mary went to a vacant bunk where she kept her clothes, and picked up her new doll. She removed its dress and looked about for a little, red, wool gown, of which she was very fond, for the day was chilly and it looked like rain. But the gown was gone, high and low she looked, but find it she could not. At last, tired out with searching, she fell asleep, and the pretty lost gown remained a mystery.

During the next few days strange things happened. On the day following one of Dolly's stockings was gone, on the next, its mate; on the next a pretty little velvet bonnet, and so on for a week. The strangest part of it was that something or somebody was bringing in little sticks of wood and cactus burrs and piling them up among the doll clothes.

At the end of the week, Jack decided to solve the mystery. He said he was going to sit up all night and see what kind of a thing was coming into the tent so regularly. He didn't do exactly what he intended to do, for by ten o'clock his eyelids grew too heavy and he was fast asleep in the vacant bunk which he had chosen for a hiding place.

Patter, patter, patter, something was coming. Jack awoke with a start of expectation. There was no moon tonight, but he had left a candle burning in a distant corner. It was all he could do to keep back a chuckle when he saw a big gray rat dart across the floor with a good sized twig in its mouth. Jack kept perfectly still and the little fellow, not even seeing him, continued its way across the floor to the bunk on which sat Jack beside the doll clothes. It clawed its way up the side of the bunk, dropped the twig, then selected a soft, woolly skirt. Then it turned and scampered away through the door and out into the sagebrush.

Jack gave a hearty laugh and at once awakened the whole family and told them his story.

"Of course," said Father, "it was a trade rat. Why didn't we think of that before? The hills are full of tiny holes where they burrow down and build their nests."

"But what about the twig?" asked Jack.

"They always pay for what they take," was the unexpected reply, "they are great fellows to steal both food and clothing, but they never take anything without replacing it with a cactus burr, a twig, a chip of wood, or something of the sort. They seem to think it wrong not to leave something in place of what they take."

"But what did they do with all my dolly's clothes?" asked Mary, "surely they can't wear them."

"Indeed no, my dear little girl," said Father, "but probably if you could find their nest, you would see them busy at work lining it with the soft, downy cloth in preparation for a family of little ones."

Mary talked and wondered about all these happenings, and you can imagine her delight when big Joe came running up to camp one day and told her he had found her rat's nest. The men had been digging on a little hill preparing to build the foundation of an extra tent. The hill was covered with rat holes and gopher holes, and Joe lifted up a shovel full of adobe and underneath was a little cave all carefully lined with warm clothing. On the soft bed lay mother rat and six tiny little fellows with eyes just opened. They were peering around with a frightened look and giving shrill little squeaks of dismay.