his successors. Did you remark the postmarks of those letters?”


“The first was from Pondicherry, the second from Dundee, and the third

from London.”


“From East London. What do you deduce from that?”


“They are all seaports. That the writer was on board of a ship.”


“Excellent. We have already a clue. There can be no doubt that the

probability—the strong probability—is that the writer was on board

of a ship. And now let us consider another point. In the case of Pondicherry,

seven weeks elapsed between the threat and its fulfilment, in Dundee it was

only some three or four days. Does that suggest anything?”


“A greater distance to travel.”


“But the letter had also a greater distance to come.”


“Then I do not see the point.”


“There is at least a presumption that the vessel in which the man or men

are is a sailing-ship. It looks as if they always send their singular warning

or token before them when starting upon their mission. You see how quickly the

deed followed the sign when it came from Dundee. If they had come from

Pondicherry in a steamer they would have arrived almost as soon as their

letter. But, as a matter of fact, seven weeks elapsed. I think that those seven

weeks represented the difference between the mail-boat which brought the letter

and the sailing vessel which brought the writer.”


“It is possible.”


“More than that. It is probable. And now you see the deadly urgency of

this new case, and why I urged young Openshaw to caution. The blow has always

fallen at the end of the time which it would take the senders to travel the

distance. But this one comes from London, and therefore we cannot count upon

delay.”


“Good God!” I cried. “What can it mean, this relentless

persecution?”


“The papers which Openshaw carried are obviously of vital importance to

the person or persons in the sailing-ship. I think that it is quite clear that