"But there it is," Cotter replied. "If these people were not so clever I should not mind. And the more you think of it, sir, the worse it becomes. Fancy that message finding its way into Slater's letter. The thing seems almost impossible; like one of those weird conjuring tricks we used to see in India. And Slater is a cautious man who runs no risks. He wrote that letter in his own hand. He posted it himself, you may be sure. And from the time that it dropped into the letter-box to the time it reached my hand, nobody but the postal officials touched it. Yet there it is, sir, there it is staring us in the face, more deadly and more dangerous than a weapon in the hands of a lunatic. Still, we have got our warning, and I dare say we shall have time——"

"But shall we?" Flower said impatiently. "Don't be too sure. You have forgotten what I told you about Miss Galloway and the mysterious hand that was trying to force a way into the conservatory. She doesn't know the significance of that attempt, and there is no reason why she should. But we know, Cotter. We know only too well that the danger is not only coming, but that it is here. Unless I am mistaken it threatens us from more quarters than one. But it is folly to discuss this matter when there is so much to be done! I have friends coming to dinner, curse it, and more are expected later in the evening. I must leave this matter to you and you must do the best you can. Prowl about the place, Cotter. Keep your eyes open. Pry into dark corners. See that all the windows are closed. Perhaps you might also explain something of this to the keeper, and ask him to chain one or two dogs up near the house. They may be useful."

Cotter acquiesced, but it was evident from the expression of his face that he did not feel in the least impressed by his employer's suggestions. This dark, intangible danger was not to be warded off by commonplace precautions. For some time after Cotter had gone Flower sat at his table thinking deeply. The longer he pondered the matter, the more inexplicable it became. Beatrice's discovery was grave enough, but this business of the registered letter was a thousand times worse. Nobody appreciated daring, audacity, and courage more than Flower. He knew what a strong asset they were in success in life; indeed, they had made him what he was. But this cleverness and audacity were far beyond his own. He took up the silken string and twisted it nervously in his fingers.

"What is it?" he murmured. "How is the thing done? And why do they send on this warning? What a horrible business it all is! To be hale and hearty one minute and be found dead the next, and not a single doctor in the world able to say how the end is brought about! And when you tackle those fellows there is no safety. Why shouldn't they bribe some dissolute scamp of an Englishman to do the same thing after showing him the way. There are dozens of men in the city of London who would put an end to me with pleasure, if they could only do so with impunity."

Flower rose wearily and left the library. He was tired of his own thoughts and for once had a longing for human society. As he went along the corridor leading to the hall, one of the maids passed him with a white face and every sign of fear and distress. With a feeling of irritation he stopped the girl and inquired what was the matter.

"What has come to the place?" he muttered. "And what have you been crying about? Aren't you Miss Galloway's maid?"

"Yes, sir," the girl murmured. "It is nothing, sir. As I was coming from the wood at the back of the house, on my way home from the village, I had a fright. I told Miss Galloway about it and she told me not to be silly. I dare say if I had looked closer, I should have found that——"

The girl's voice trailed off incoherently and Flower suffered her to go away. It was not for him to trouble himself over the fears and fancies of his servants, and at any other time he would have shown no curiosity. But in the light of recent events even a little thing like this had its significance. At any rate, he would ask Beatrice about it.

Beatrice was in the drawing-room putting the finishing touches to the flowers. It would soon be dinner-time.

"I have just met your maid," Flower said. "What on earth is the matter with the girl? She looks as if she had seen a ghost. I hope to goodness the servants haven't been talking and making a lot of mischief about this story that a former lord of Maldon Grange walks the corridors at night. If there is one form of superstition I detest more than another, it is that."