It must not be supposed that this was arrived at in a single draft. Greg was still writing when Hickey called up to him that it was time to start, whereupon he finished in a hurry and carried it down to its hiding-place. To Hickey he said: "I suppose they'll want you to carry them home from the concert. While it's going on you can hang around and pick up any business that offers. But first of all after you have dropped them at the hall meet me at the corner of Sixth and Forty-third so that I can see if she left anything for me on the way down." Hickey drove out of the yard with the sly grin that provoked Greg, or half provoked him, for at the same time he was well assured that he was faithfully served in Hickey. Greg looked around the taxi-yard. Three of the cabs were in, the owners presumably sleeping inside. Greg peeped through the windows considering which one would best suit his purpose; the morose Blossom, honest, thick-witted Bull Tandy, or old Pa Simmons. He decided on the latter; Pa Simmons, red and white as a snow-apple, was so indubitably the cabman, no one would ever suspect him of acting in another capacity. Pa Simmons was never seen without his cabman's overcoat; he seemed atrophied from the waist down, and one guessed that he had not walked more than a hundred yards at a time in thirty years. In imagination he still dwelt fondly on the days when he had driven a gentleman's private hansom; now his vehicle was an antique Pack-Arrow that still retained a faded air of luxury in its dim enamel and worn upholstery. At Greg's summons Pa Simmons sprang up blinking rapidly, on the alert for a fare. There was something at once plucky, piteous and comical in his assumption of youthful sprightliness. His face fell at the sight of Greg, for he suspected a practical joke. Yet he and all the cabmen liked Greg for his unaffected friendly ways. All knew by now that Greg was involved in a fascinating mystery. "Will you take a job for me, Pa?" asked Greg. "On the level?" asked Pa Simmons warily. "Dead level. By the day, with gasoline and all expenses. I want you to do a little detective work." Pa Simmons' blue eyes brightened. "I'm your man! I allus said I'd make a A1 sleuth. Lay the matter open to me. It'll be a pleasant change not to be looking for fares for a few days." An arrangement was quickly effected, and Pa Simmons, armed with a careful description of de Socotra, was dispatched to the address on Thirty-sixth Street. Half an hour later Greg was impatiently waiting at the corner of Sixth Avenue and Forty-third Street. Down the block he could see the cabs driving up to Harmony Hall, and the two streams of pedestrians converging at the door. As he waited he took out his note-book and wrote: