signalling and wireless, a signaller of the service, two other officers equally expert in reading the Morse code, while I myself have qualified both in Morse and wireless, and hold the Postmaster-General's licence.
On the previous evening an all-night vigil had been kept, and messages had been read, but I only here record my own experiences of this exciting spy-hunt. On reaching our point of vantage I learned that suspicion had first been aroused by a mysterious and intense white light being shown from a window in the country mansion in question, which was situated upon so strategic a point that it could be seen very many miles in the direction of London. And there, sure enough, was the one brilliant light—at all other windows of the house the blinds being drawn—shining like a beacon all over the country. It had shone first at 6.30 p.m. that night, and, as I watched, it showed till 6.48, when it disappeared. After three minutes it was shown till 7.30 exactly, when suddenly it signalled in Morse the code-letters "S. M." repeated twice, and then disappeared till 9 o'clock, when again the same signal was made. The light remained full on for ten minutes, and was then suddenly switched off.
This was certainly remarkable. The officers with me—all experts in signalling—were unanimous as to the two letters, and also to their repetition. These signals, I learned, had been seen times without number, but until the smart young officer who had called upon me had noticed them, no action had been taken.
Having established that mysterious signalling was really in progress, I set forth upon further investigation. Taking my own signalling-appara-
