Cornelius uttered a cry, and was nearly fainting.

"Oh!" muttered he, "my God, my God, Thou dost reward me for my innocence and my captivity, as Thou hast allowed two such flowers to grow at the grated window of my prison!"

The tulip was beautiful, splendid, magnificent; its stem was more than eighteen inches high; it rose from out of four green leaves, which were as smooth and straight as iron lance-heads; the whole of the flower was as black and shining as jet.

"Rosa," said Cornelius, almost gasping, "Rosa, there is not one moment to lose in writing the letter."

"It is written, my dearest Cornelius," said Rosa.

"Is it, indeed?"

"Whilst the tulip opened I wrote it myself, for I did not wish to lose a moment. Here is the letter, and tell me whether you approve of it."

Cornelius took the letter, and read, in a handwriting which was much improved even since the last little note he had received from Rosa, as follows: --

"Mynheer President, -- The black tulip is about to open, perhaps in ten minutes. As soon as it is open, I shall send a messenger to you, with the request that you will come and fetch it in person from the fortress at Loewestein. I am the daughter of the jailer, Gryphus, almost as much of a captive as the prisoners of my father. I cannot, therefore, bring to you this wonderful flower. This is the reason why I beg you to come and fetch it yourself.

"It is my wish that it should be called Rosa Barlaensis.

"It has opened; it is perfectly black; come, Mynheer President, come.

"I have the honour to be your humble servant,

"Rosa Gryphus.

"That's it, dear Rosa, that's it. Your letter is admirable! I could not have written it with such beautiful simplicity. You will give to the committee all the information that will be required of you. They will then know how the tulip has been grown, how much care and anxiety, and how many sleepless nights, it has cost. But for the present not a minute must be lost. The messenger! the messenger!"

"What's the name of the President?"

"Give me the letter, I will direct it. Oh, he is very well known: it is Mynheer van Systens, the burgomaster of Haarlem; give it to me, Rosa, give it to me."

And with a trembling hand Cornelius wrote the address, --

"To Mynheer Peter van Systens, Burgomaster, and President of the Horticultural Society of Haarlem."

"And now, Rosa, go, go," said Cornelius, "and let us implore the protection of God, who has so kindly watched over us until now."

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.