s
one of the best things for keeping cows in good health."

Meanwhile they had driven up to a farmhouse, almost as large as their
own, and the mistress, who was arranging her pans for the evening
milking, said they might have cold milk then, or fresh warm milk if they
would wait a little while until the cows came home.

Under the back porch was a cage with a little Owl in it, and the woman
said it belonged to her boy. Joe, for that was his name, was about Rap's
age, and soon made friends with them. They told him where they had been
spending the day, and about their uncle's wonder room, and the birds at
Orchard Farm. "Have you got a Hummingbird's nest on your farm, and a
Swallow chimney?" Joe asked anxiously.

"No, not exactly," said Nat, hesitating. "There are some birds in Uncle
Roy's chimney, but we haven't found a Hummingbird's nest yet, though
there are lots of the birds about the garden."

"Well, there's a Hummingbird's nest in our crab-apple tree, and we own
the biggest Swallow chimney there is in the county! Pa says so, and he
knows," said Joe proudly. "If you'll come with me and not grab the nest,
I'll show it to you. It's a widow Hummingbird, too. I've never seen her
mate since she began to set, but before that he was always flyin' round
the honeysuckles and laylocks, so I'm sure he is dead."

"May I come too?" asked the Doctor.

"Pleased to have you, sir," said Joe, making a stiff little bow. "I'd
have asked you, only most men folks don't set much store by birds 'nless
they are the kind they go gunnin' for. Only pa does. He likes any kind
o' bird, whether it sings or not, and he's powerful fond of the Swallows
in our chimney. He says they eat the flies and things that tease the
cows down in the pasture, and since those Swallows came to our chimney
we haven't had to put fly-sheets on the oxen when they are in the
pasture--not once."

"Now, children, you see what good the Sky Sweepers do," said the Doctor.

"Sky Sweepers! We don't call 'em that! We call 'em Chimney Swallows!"

Then the children told Joe about the Bird Brotherhoods.

"Stand on this box," said Joe to Dodo, "and look hard at that small
slantways branch, with the little bunch on it!"

"The little round bunch that looks like soft green moss?"

"Yes. Well, that's the Hummer's nest!"

"Oh! oh!" cried Dodo, forgetting to whisper, "I see a mite of a tail and
a sharp needle beak sticking over the edge!"

This was too much for Mrs. Hummer,