Rosa watched the flower-pot with an interest which betrayed to Boxtel the real value of the object enclosed in it.

This object could not be anything else but the second bulb, that is to say, the quintessence of all the hopes of the prisoner.

When the nights threatened to be too cold, Rosa took in the flower-pot.

Well, it was then quite evident she was following the instructions of Cornelius, who was afraid of the bulb being killed by frost.

When the sun became too hot, Rosa likewise took in the pot from eleven in the morning until two in the afternoon.

Another proof: Cornelius was afraid lest the soil should become too dry.

But when the first leaves peeped out of the earth Boxtel was fully convinced; and his telescope left him no longer in any uncertainty before they had grown one inch in height.

Cornelius possessed two bulbs, and the second was intrusted to the love and care of Rosa.

For it may well be imagined that the tender secret of the two lovers had not escaped the prying curiosity of Boxtel.

The question, therefore, was how to wrest the second bulb from the care of Rosa.

Certainly this was no easy task.

Rosa watched over her tulip as a mother over her child, or a dove over her eggs.

Rosa never left her room during the day, and, more than that, strange to say, she never left it in the evening.

For seven days Boxtel in vain watched Rosa; she was always at her post.

This happened during those seven days which made Cornelius so unhappy, depriving him at the same time of all news of Rosa and of his tulip.

Would the coolness between Rosa and Cornelius last for ever?

This would have made the theft much more difficult than Mynheer Isaac had at first expected.

We say the theft, for Isaac had simply made up his mind to steal the tulip; and as it grew in the most profound secrecy, and as, moreover, his word, being that of a renowned tulip-grower, would any day be taken against that of an unknown girl without any knowledge of horticulture, or against that of a prisoner convicted of high treason, he confidently hoped that, having once got possession of the bulb, he would be certain to obtain the prize; and then the tulip, instead of being called Tulipa nigra Barlaensis, would go down to posterity under the name of Tulipa nigra Boxtellensis or Boxtellea.

Mynheer Isaac had not yet quite decided which of these two names he would give to the tulip, but, as both meant the same thing, this was, after all, not the important point.

The point was to steal the tulip. But in order that Boxtel might steal the tulip, it was necessary that Rosa should leave her room.

Great therefore was his joy when he saw the usual evening meetings of the lovers resumed.

He first of all took advantage of Rosa's absence to make himself fully acquainted with all the peculiarities of the door of her chamber. The lock was a double one and in good order, but Rosa always took the key with her.

Boxtel at first entertained an idea of stealing the key, but it soon occurred to him, not only that it would be exceedingly difficult to abstract it from her pocket, but also that, when she perceived her loss, she would not leave her room until the lock was changed, and then Boxtel's first theft would be useless.