Graham never completed his thought. From the right, not far away, came the unmistakable ring of shod hoofs on concrete, followed by a mighty splash and an outburst of women’s cries and laughter. Quickly the cries turned to alarm, accompanied by the sounds of a prodigious splashing and floundering as of some huge, drowning beast. Dick bent his head and leaped his horse through the lilacs, Graham, on Altadena, followed at his heels. They emerged in a blaze of sunshine, on an open space among the trees, and Graham came upon as unexpected a picture as he had ever chanced upon in his life.

Tree-surrounded, the heart of the open space was a tank, four-sided of concrete. The upper end of the tank, full width, was a broad spillway, sheened with an inch of smooth-slipping water. The sides were perpendicular.