Frank to glance up at the sky again. With remarkable rapidity, the huge cloud he had previously noticed had spread over the entire sky, causing gloom to spread over the bay. A few white caps were apparent on the surface of the water and there was a splatter of rain.
"Guess we'd better turn back," he said, turning to the others.
"Why, what's the matter?" asked Callie.
"Storm coming up."
The girls had been so intent on the chase that they had not noticed the lowering clouds, but now Callie gave a murmur of astonishment.
"Why, it's going to pour! And I haven't brought my slicker with me. We'll be drenched."
"But what about Biff and Chet?" exclaimed Iola.
"I think they'll turn back too when they see what they're heading into," replied Frank. "It looks like a bad storm."
As though in corroboration of his words, a sheet of lightning and a violent clap of thunder heralded the beginning of the downpour. The wind came in from the sea with a violence that surprised them, came whistling down across the bay over a wide line of tossing white-caps, driving before it a leaden wall of rain.
The two motorboats in the lead were blotted from view, although Frank had seen that Tony
