Mr. Marx's Secret by E. Phillips Oppenheim

For the first time in my life I was in London -- and alone. There had been no reply from Mr. Marx to the telegrams commanding his instant return, and so on the third morning after my arrival at Ravenor Castle I quitted it again to go in search of him. Accustomed though he was to conceal his feelings, and admirably though he succeeded in doing so in the presence of his guests, I could see that Mr. Ravenor was deeply anxious to have the suspicions which my story had awakened either dispelled or confirmed. Nor, indeed, although their purport was scarcely so clear to me, was I less so.

I suppose that no one, especially if he had never before been in a great city, could pass across London for the first time without some emotion of wonder. To me it was like entering an unknown world. The vast throng of people, the ceaseless din of traffic, and the huge buildings, all filled me with amazement which, as we drove through the Strand to Northumberland Avenue, grew into bewilderment. Only the recollection of my mission and its grave import recalled me to myself as the cab drew up before the Hotel Metropole.