“And who and what may she be?  I have heard of water-women, sometimes called mermaids, but never before did I hear of a fire-woman.”

“She don’t live in fire,” said Greta; “she sells it.  What do the poor people in your country do in summer without a fire-woman?  Come and look in.”

[Illustration:  AT THE FIRE-WOMAN’S.]

By this time they had reached the place.  Over the door was the sign “Water en vuur te koop."[1] It was not necessary for the children to go inside.  They could see the whole apartment through the wide-open door-way.  An old woman stood by a stove, or great oven, with a pair of tongs, taking up pieces of burning peat and dropping them into the buckets of the children, and then filling their tea-kettles with boiling water from great copper tanks on the stove.  For this each child paid her a Dutch cent, which is less than half of one of ours.

    [Footnote 1:  “Water and fire to sell.”]

“I understand it,” said Will, after they had stood at the door some time, amused at the scene.  “This saves poor people the expense of a fire in the summer-time.  They send here for hot water to make their tea.”

“Yes,” said Greta, “and for the burning peat which cooks the potatoes and the sausage for their supper.”

“Why don’t they use coal?” asked Martin.  “It is ever so much better.”

“No, the peat answers their purpose much better,” said Will.  “It burns slowly, and gives out a good deal of heat for a long time.”

“And the smell of it is so delicious,” added Greta.

A little further on; the children came out on an open space, which gave them a good view of the surrounding flat country, and of the wind-mills that stand about Zaandam—­a forest of towers.  It was a marvelous sight.  Hundreds of giant arms were beating the air, as if guarding the town from invisible enemies.

Greta was proud and pleased that her cousins were so impressed with the great numbers of towers and the myriads of gigantic whirling spokes.

“My father says there is nothing grander than this in all Holland,” she said.  “There are four hundred of them, and more, but you can’t see them all from here.  Do you see that mill over yonder?  That is my father’s, and we are going there to-morrow.”

The boys could not distinguish one tower from another at that distance.

“What kind of mill is it?” asked Will.

“A flour-mill.”

“Are all these flour-mills?”

“Oh no!  There are saw-mills, colza-oil mills, mustard-mills, flax-mills, and other kinds I don’t remember.”

It was now nearly supper-time, and the little group returned home.

The next morning, the whole party—­four grown-up people, four youngsters, and four boats (the “Wilhelmina,” the “Gouda,” the “America,” and the “Columbus")—­were all taken up the Zaan River in a row-boat for about three miles, and then up a small stream to the mill where they were to spend the day.