Pieter and Wilhelmina were never tired of hearing their father tell of the time all Holland went almost crazy over tulips. This was nearly three hundred years ago, after the tulip had just been brought to Holland, and was a much rarer flower than it is to-day. It got to be the fashion for every one to raise tulips, and they sold for large sums of money. Several thousands of "guldens" (a "gulden" is the chief Dutch coin) were paid for a single bulb. People sold their houses and lands to buy tulips, which they were able to sell again at a great profit. Everybody went wild over these beautiful flowers, rich and poor alike, men, women, and children. Everybody bought and sold tulips, and nobody thought or talked about anything but the price of tulips. At last the Dutch government put a stop to this nonsense, and down tumbled the prices of tulips. In spite of this, the Dutch love for the flower still continued, and to-day one may see these great fields of tulips and hyacinths and other bulb-plants covering miles and miles of the surface of Holland, just as do wheat-fields in other lands. There is a large and continually growing trade in these plants going on all over Holland, and Mynheer Joost was always able to sell his plants for as big a price as any others in the market. The principal tulip-gardens are in the vicinities of the cities of Leyden and Haarlem, and from where Wilhelmina and Pieter now stood, in the midst of their father's tulip-beds, they could see the tower of the Groote Kerk, or Great Church, of Haarlem. Mynheer Joost sold a very rare variety, which only he knew how to grow, and which was named the "Joost;" it was almost pure black, with only a tiny red tip on each petal. It was the pride of his heart, and he often told the children that he hoped some day to be able to turn it into a pure black one; and then what a fortune it would bring them all! So Pieter and Wilhelmina watched its growth almost as carefully as did their father. "There is Mynheer and the father now, looking at the 'great tulip,'" said Pieter. This was the way they always spoke of this wonderful plant. But Wilhelmina suddenly grew shy at the sight of the great man. "Come, let us hide," she said, and she tried to draw Pieter behind one of the large glass houses, in which were kept many of the rarer plants. But Pieter wanted to see Mynheer Van der Veer, the well-known merchant who owned so many big warehouses in Amsterdam, and also a tall, fine house on one of the "grachten" of that city, which is the name given to the canals.