In the afternoon, among other purchases, a more convenient case was bought for the model, and in this it was packed with the plans and papers which explained its construction, ready for the evening journey.
The two friends dined together at six in Colston's rooms, and at seven sharp his servant announced that the cab was at the door. Within ten minutes they were bowling along the Embankment towards Westminster Bridge in a luxuriously appointed hansom of the newest type, with the precious case lying across their knees.
"This is a comfortable cab," said Arnold, when they had gone a hundred yards or so. "By the way, how does the man know where to go? I didn't hear you give him any directions."
"None were necessary," was the reply. "This cab, like a good many others in London, belongs to the Brotherhood, and the man who is driving is one of the Outer Circle. Our Jehus are the most useful spies that we have. Many is the secret of the enemy that we have learnt from, and many is the secret police agent who has been driven to his rendezvous by a Terrorist who has heard every word that has been spoken on the journey."
"How on earth is that managed?"
"Every one of the cabs is fitted with a telephonic arrangement communicating with the roof. The driver has only to button the wire of the transmitter up inside his coat so that the transmitter itself lies near to his ear, and he can hear even a whisper inside the cab.
"The man who is driving us, for instance, has a sort of retainer from the Russian Embassy to be on hand at certain hours on certain nights in the week. Our cabs are all better horsed, better appointed, and better driven than any others in London, and, consequently, they are favourites, especially among the young attachés, and are nearly always employed by them on their secret missions or love affairs, which, by the way, are very often the same thing. Our own Jehu has a job on to-night, from which we expect some results that will mystify the enemy not a little. We got our first suspicions of Ainsworth from a few incautious words that he spoke in one of our cabs."
"It's a splendid system, I should think, for discovering the movements of your enemies," said Arnold, not without an uncomfortable reflection on the fact that he was himself now completely in the power of this terrible organisation, which had keen eyes and ready hands in every capital of the civilised world. "But how do you guard against treachery? It is well known that all the Governments of Europe are spending money like water to unearth this mystery of the Terror. Surely all your men cannot be incorruptible."
"Practically they are so. The very mystery which enshrouds all our actions makes them so. We have had a few traitors, of course; but as none of them has ever survived his treachery by twenty-four hours, a bribe has lost its attraction for the rest."
In such conversation as this the time was passed, while the cab crossed the river and made its way rapidly and easily along Kennington Road and Clapham Road to Clapham Common. At length it turned into the drive of one of those solid abodes of pretentious respectability which front the Common, and pulled up before a big stucco portico.