And in fact the poor young people were in great need of protection.

They had never been so near the destruction of their hopes as at this moment, when they thought themselves certain of their fulfilment.

The reader cannot but have recognized in Jacob our old friend, or rather enemy, Isaac Boxtel, and has guessed, no doubt, that this worthy had followed from the Buytenhof to Loewestein the object of his love and the object of his hatred, - the black tulip and Cornelius van Baerle.

What no one but a tulip-fancier, and an envious tulip-fancier, could have discovered, - the existence of the bulbs and the endeavours of the prisoner, - jealousy had enabled Boxtel, if not to discover, at least to guess.

We have seen him, more successful under the name of Jacob than under that of Isaac, gain the friendship of Gryphus, which for several months he cultivated by means of the best Genievre ever distilled from the Texel to Antwerp, and he lulled the suspicion of the jealous turnkey by holding out to him the flattering prospect of his designing to marry Rosa.

Besides thus offering a bait to the ambition of the father, he managed, at the same time, to interest his zeal as a jailer, picturing to him in the blackest colours the learned prisoner whom Gryphus had in his keeping, and who, as the sham Jacob had it, was in league with Satan, to the detriment of his Highness the Prince of Orange.

At first he had also made some way with Rosa; not, indeed, in her affections, but inasmuch as, by talking to her of marriage and of love, he had evaded all the suspicions which he might otherwise have excited.

We have seen how his imprudence in following Rosa into the garden had unmasked him in the eyes of the young damsel, and how the instinctive fears of Cornelius had put the two lovers on their guard against him.

The reader will remember that the first cause of uneasiness was given to the prisoner by the rage of Jacob when Gryphus crushed the first bulb. In that moment Boxtel's exasperation was the more fierce, as, though suspecting that Cornelius possessed a second bulb, he by no means felt sure of it.

From that moment he began to dodge the steps of Rosa, not only following her to the garden, but also to the lobbies.

Only as this time he followed her in the night, and bare-footed, he was neither seen nor heard except once, when Rosa thought she saw something like a shadow on the staircase.

Her discovery, however, was made too late, as Boxtel had heard from the mouth of the prisoner himself that a second bulb existed.

Taken in by the stratagem of Rosa, who had feigned to put it in the ground, and entertaining no doubt that this little farce had been played in order to force him to betray himself, he redoubled his precaution, and employed every means suggested by his crafty nature to watch the others without being watched himself.

He saw Rosa conveying a large flower-pot of white earthenware from her father's kitchen to her bedroom. He saw Rosa washing in pails of water her pretty little hands, begrimed as they were with the mould which she had handled, to give her tulip the best soil possible.

And at last he hired, just opposite Rosa's window, a little attic, distant enough not to allow him to be recognized with the naked eye, but sufficiently near to enable him, with the help of his telescope, to watch everything that was going on at the Loewestein in Rosa's room, just as at Dort he had watched the dry-room of Cornelius.

He had not been installed more than three days in his attic before all his doubts were removed.

From morning to sunset the flower-pot was in the window, and, like those charming female figures of Mieris and Metzys, Rosa appeared at that window as in a frame, formed by the first budding sprays of the wild vine and the honeysuckle encircling her window.

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.

He thought it, therefore, better to employ a different expedient. He collected as many keys as he could, and tried all of them during one of those delightful hours which Rosa and Cornelius passed together at the grating of the cell.

Two of the keys entered the lock, and one of them turned round once, but not the second time.

There was, therefore, only a little to be done to this key.

Boxtel covered it with a slight coat of wax, and when he thus renewed the experiment, the obstacle which prevented the key from being turned a second time left its impression on the wax.

It cost Boxtel two days more to bring his key to perfection, with the aid of a small file.

Rosa's door thus opened without noise and without difficulty, and Boxtel found himself in her room alone with the tulip.

The first guilty act of Boxtel had been to climb over a wall in order to dig up the tulip; the second, to introduce himself into the dry-room of Cornelius, through an open window; and the third, to enter Rosa's room by means of a false key.

Thus envy urged Boxtel on with rapid steps in the career of crime.

Boxtel, as we have said, was alone with the tulip.

A common thief would have taken the pot under his arm, and carried it off.

But Boxtel was not a common thief, and he reflected.

It was not yet certain, although very probable, that the tulip would flower black; if, therefore, he stole it now, he not only might be committing a useless crime, but also the theft might be discovered in the time which must elapse until the flower should open.

He therefore - as being in possession of the key, he might enter Rosa's chamber whenever he liked - thought it better to wait and to take it either an hour before or after opening, and to start on the instant to Haarlem, where the tulip would be before the judges of the committee before any one else could put in a reclamation.

Should any one then reclaim it, Boxtel would in his turn charge him or her with theft.

This was a deep-laid scheme, and quite worthy of its author.

Thus, every evening during that delightful hour which the two lovers passed together at the grated window, Boxtel entered Rosa's chamber to watch the progress which the black tulip had made towards flowering.

On the evening at which we have arrived he was going to enter according to custom; but the two lovers, as we have seen, only exchanged a few words before Cornelius sent Rosa back to watch over the tulip.

Seeing Rosa enter her room ten minutes after she had left it, Boxtel guessed that the tulip had opened, or was about to open.

During that night, therefore, the great blow was to be struck. Boxtel presented himself before Gryphus with a double supply of Genievre, that is to say, with a bottle in each pocket.

Gryphus being once fuddled, Boxtel was very nearly master of the house.

At eleven o'clock Gryphus was dead drunk. At two in the morning Boxtel saw Rosa leaving the chamber; but evidently she held in her arms something which she carried with great care.

He did not doubt that this was the black tulip which was in flower.

But what was she going to do with it? Would she set out that instant to Haarlem with it?

It was not possible that a young girl should undertake such a journey alone during the night.

Was she only going to show the tulip to Cornelius? This was more likely.

He followed Rosa in his stocking feet, walking on tiptoe.

He saw her approach the grated window. He heard her calling Cornelius. By the light of the dark lantern he saw the tulip open, and black as the night in which he was hidden.

He heard the plan concerted between Cornelius and Rosa to send a messenger to Haarlem. He saw the lips of the lovers meet, and then heard Cornelius send Rosa away.

He saw Rosa extinguish the light and return to her chamber. Ten minutes after, he saw her leave the room again, and lock it twice.

Boxtel, who saw all this whilst hiding himself on the landing-place of the staircase above, descended step by step from his story as Rosa descended from hers; so that, when she touched with her light foot the lowest step of the staircase, Boxtel touched with a still lighter hand the lock of Rosa's chamber.

And in that hand, it must be understood, he held the false key which opened Rosa's door as easily as did the real one.

And this is why, in the beginning of the chapter, we said that the poor young people were in great need of the protection of God.