Frayne drew from this envelope a sheet of notepaper, which bore neither address nor date, merely the words—
"At Ealing, at 10 p.m., on the twenty-ninth of August, where the two C's meet."
"Ah, an appointment," remarked Frayne. Then, looking at the post-mark, he added: "It was posted the day before yesterday at Bridlington. I wonder what it means?"
"I see it is addressed to Mr. Gregory!" I pointed out, "not to the dead man."
"Then the old man had an appointment on the twenty-ninth of August somewhere in Ealing—where the two C's meet. I wonder where that can be? Some agreed-on spot, I suppose, where two persons, whose initials are C, are in the habit of meeting."
"Probably," was my reply. But I was reflecting deeply.
In the wallet were four five-pound notes; a few of Gregory's cards; a letter from a local charity, thanking him for a contribution of two guineas; and a piece of paper bearing a number of very elaborate calculations, apparently of measured paces.
It seemed as though the writer had been working out some very difficult problem of distances, for the half-sheet of quarto paper was absolutely covered with minute pencilled figures; lengths in metres apparently.
I looked at them, and at a glance saw that old Gregory had either received his education abroad, or had lived for a long time upon the continent when a young man. Why? Because, when he made a figure seven, he drew a short cross-stroke half-way up the downward stroke, in order, as foreigners do, to distinguish it from the figure one.