On the left lay the black solitude of Central Park, on the right the varied architecture of New York's millionaire dwellings.
Devar and the policeman talked cheerfully enough, but Curtis was wrapped in his own musings till the rear lamp of the gray car suddenly curved to the left and vanished.
"He has turned into the Parkway at 110th Street," said McCulloch, and Curtis awoke with a start to a sense of his surroundings.
"I suppose he's making for St.Nicholas Avenue," went on the roundsman.
"Why ?" demanded Curtis, whose recollections of map-study would have reminded him, in other conditions, that the avenue named by McCulloch is one of the few which slant across the city's rectangles.
"Well, sir, it's only a guess, but St.Nicholas Avenue is a short cut to Washington Heights, and cars often follow that route.

Yes, there he goes!" For an instant they caught a fleeting glimpse of Lenox Avenue, which runs parallel with Fifth, and then they were bowling along St.Nicholas Avenue.

After a half-mile or less, they crossed Eighth Avenue at an acute angle, but the gray car kept steadily on, and soon was skirting St.Nicholas Park.
Thenceforth another mile and a half counted as little until the flying automobile gained the Harlem River Speedway.

Here the pace improved.
There was practically no traffic to interfere with progress now, and Brodie had to maintain an equable rate of forty miles an hour in order to keep within sight of his quarry.
At last, by way of Nagle and Amsterdam Avenues, they regained Broadway itself, at the point where its many sinuosities end at the bridges over the Harlem River and Spuyten Creek.
By this time, McCulloch was undeniably anxious.

Many a mile separated him from the busy activities of Madison Square and its surroundings, and the main roads of the State of New York were opening up their possibilities.