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, 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.

“Yes, it was by their light, and that of the lady’s bedroom candle, that the burglars saw their way about.”

“And what did they take?”

“Well, they did not take much — only half a dozen articles of plate off the sideboard. Lady Brackenstall thinks that they were themselves so disturbed by the death of Sir Eustace that they did not ransack the house, as they would otherwise have done.”

“No doubt that is true, and yet they drank some wine, I understand.”

“To steady their nerves.”

“Exactly. These three glasses upon the sideboard have been untouched, I suppose?”

“Yes, and the bottle stands as they left it.”

“Let us look at it. Halloa, halloa! What is this?”

The three glasses were grouped together, all of them tinged with wine, and one of them containing some dregs of beeswing. The bottle stood near them, two-thirds full, and beside it lay a long, deeply stained cork. Its appearance and the dust upon the bottle showed that it was no common vintage which the murderers had enjoyed.

A change had come over Holmes’s manner. He had lost his listless expression, and again I saw an alert light of interest in his keen, deep-set eyes. He raised the cork and examined it minutely.

“How did they draw it?” he asked.

Hopkins pointed to a half-opened drawer. In it lay some table linen and a large corkscrew.

“Did Lady Brackenstall say that screw was used?”

“No, you remember that she was senseless at the moment when the bottle was opened.”

“Quite so. As a matter of fact, that screw was not used. This bottle was opened by a pocket screw, probably contained in a knife, and not more than an inch and a half long. If you will examine the top of the cork, you will observe that the screw was driven in three times before the cork was extracted. It has never been transfixed. This long screw would have transfixed it and drawn it up with a single pull. When you catch this fellow, you will find that he has one of these multiplex knives in his possession.”

“Excellent!” said Hopkins.

“But these glasses do puzzle me, I confess. Lady Brackenstall actually saw the three men drinking, did she not?”

“Yes; she was clear about that.”

“Then there is an end of it. What more is to be said? And yet, you must admit, that the three glasses are very remarkable, Hopkins. What? You see nothing remarkable? Well, well, let it pass. Perhaps, when a man has special knowledge and special powers like my own, it rather encourages him to seek a complex explanation when a simpler one is at hand. Of course, it must be a mere chance about the glasses. Well, good-morning, Hopkins. I don’t see that I can be of any use to you, and you appear to have your case very clear. You will let me know when Randall is arrested, and any further developments which may occur. I trust that I shall soon have to congratulate you upon a successful conclusion. Come, Watson, I fancy that we may employ ourselves more profitably at home.”