unless you live at the
North Pole. Up there it gets so cold that sometimes alcohol will
became as thick as molasses, and then it is not of any use in a
thermometer. But mercury will not freeze, even at the North Pole.

The word thermometer means something by which heat can be measured.
"Thermos" is a Greek word, meaning heat, and "Meter" means to measure.
Though of course a thermometer will measure cold as well as heat.

"Is it cold enough?" asked Hal, as Daddy Blake came back from looking
at the thermometer.

"Not quite," his father answered. "But the mercury is going down the
tube."

"What makes it go down?" asked Mab.

"Well, let me think a minute, and I'll see if I can make it simple
enough so you can understand," said Daddy Blake.

Those of you who have read the other "Daddy" books know how many
things Mr. Blake told his children, and what good times Hal and Mab
had with him. He was always taking them somewhere, and often one or
the other of the children would call out:

"Oh, Daddy is going to take us walking!"

Sometimes perhaps it might not be for a walk. It might be for a trip
in the steam cars. But, wherever it was, Hal and Mab were always ready
to go with their father.

In the first book I told you how Daddy Blake took Hal and Mab camping.
They went to live in the woods in a white tent and had lots of fun.
Once they were frightened in the night, but it was only because
Roly-Poly, their poodle dog--

But there, I'm not going to spoil it by telling you, when you might
want to read the book for yourself.

In the second volume, called "Daddy Takes Us Fishing," I made up a
story about how Hal and Mab went to the seashore cottage, and learned
to catch different kinds of fish; even the queer, pinching crabs, that
turned red when you boiled them.

Once Mab fell overboard, and the children nearly drifted out to sea,
but they got safely back. After that they went to the big animal show.
And in the book "Daddy Takes Us to the Circus," I told you how Hal and
Mab were accidentally taken away in one of the circus wagons, and how
they traveled all night. And the next day they rode on the elephant's
back, and also on a camel's and they went in the big parade. Oh! it
was just wonderful the adventures they had!

Hal and Mab lived with their papa and mamma, and Aunt Lolly, in a fine
house in the city. But they often went to the country and to other
places where they had good times. In the family was also Uncle