I own, therefore, that it was with considerable trepidation that I left the detective on entering the Mall and wandered slowly along beneath the trees, while he crossed and entered the park himself. In that thoroughfare, which forms a short and pleasant cut for taxis going eastward from Victoria station, there was considerable traffic at that hour. The sky was blue, and the June sun shone warmly through the trees, giving the Londoner a foretaste of summer, and causing him to think of straw hats, flannels and holiday diversions. A bright day in a London park at once arouses thoughts of the country or the sea. With my face set towards the long, regular facade of Buckingham Palace--a grey picture with little artistic touches of red, the scarlet coats of the Guards--I wondered what would be the outcome of this attempt to obtain a clue. That thin squeaky voice sounded in my ear as distinctly at that moment as it had done on the previous night, a weird summons from one unknown. At last, just as Big Ben, showing high across the trees, chimed and boomed forth the hour of noon, I entered one of the small gates of the park and strolled along the gravelled walk down to the edge of the ornamental water, where, for some minutes, I stood watching a group of children feeding the water-fowl. Though trying to look unconcerned, my eyes were ever on the alert. I had expected to see Boyd, but there was no sign of him, therefore I strolled along, passing the end of the water, the exact spot indicated. There was no one there beyond half a dozen school children feeding the birds with portions of dinners brought with them from distant homes. Undecided whether to halt there, I kept my attention fixed upon the children, then, fearing to annoy Boyd by remaining at that point, I strolled slowly along the shore in the direction of Birdcage Walk. The detective had certainly concealed himself successfully, for although I kept my eyes on the watch I could discover no sign of him. The hour of the appointment had passed, but, not daring to turn back to look, I kept straight on, until, at some distance beyond, I came to a seat beside the path and there I rested, drawing a newspaper from my pocket and pretending to read. Unfortunately, from where I sat, at a point opposite the Wellington Barracks, I could obtain no view of the meeting-place, and although Big Ben struck the quarter I was compelled to remain there inactive, watching furtively the few passers-by. With a diligence perhaps unworthy of a journalist I read and re-read my newspaper for nearly half an hour, and in the course of that time the people who went along did not number a dozen. Of none of these did I entertain any suspicion. They included a couple of soldiers, two or three old women, a lady with a small child, a couple of nurses with children, a park-keeper, and a bank clerk with his wallet chained to his belt.