Fortunately he drew back in time to escape recognition, and to watch Martin enter a taxi and drive away. Another taxi was near the kerb, therefore in it he followed the foreigner away to North London, to a small, rather dingy shop where electrical appliances were sold—a shop well known to wireless experimenters who are in search of odd and second-hand apparatus and bargains of every description.
The man remained in the place for nearly half an hour, but so blocked up was window and door that the passer-by in Chalk Farm Road could not get a glimpse within. The establishment was one of the most antique in London, and patronised widely by amateurs as well as the greatest scientists in that city.
Presently he came forth bearing a good-sized wooden box, which he put on the front of the taxi, and then drove to the Hotel Russell, where he entered and dismissed the taxi.
A judicious chat with the hall-porter revealed the fact that the name under which the stranger was known was Mr. Charles Lazarus. And he declared himself as a French subject.
With this knowledge Geoffrey engaged a room at the hotel and started to keep strict surveillance upon the stranger. The man’s movements were most mysterious. That same evening he met three other men, palpably foreigners, at the Café Royal, where they dined together expensively, and afterwards all four drove in a taxi to a big double-fronted house in Maresfield Gardens, Hampstead.
Some time after they had been inside, Geoffrey managed to slip into the small front garden, and, approaching stealthily one of the lower bay windows, listened. He distinguished men’s voices, though he could not hear what words were being uttered. He thought they were speaking in French.
Suddenly he heard a sharp metallic clicking. Instantly he recognised it as the tick of a Morse telegraph “sounder.” The letters of the alphabet were being sent both rapidly and well. There was no message—merely the letters A to Z, followed quickly by the numbers 0 to 9. They were evidently testing some apparatus.
He looked about to see any telegraph wires around the house, but the night was too dark and overcast to enable him to distinguish anything.
What was happening within, he wondered? The sound was certainly that of either a post-office telegraph transmitter or receiving “inker.” The click was too familiar and too pronounced for him to be mistaken.
Fearing discovery he withdrew, and then he waited in a dark doorway for the reappearance of the man upon whom he was keeping observation. Martin came out very soon after eleven o’clock, and walking down to Swiss Cottage station, took train, and made his way back to the hotel.