"Keep back!" shouted the man. "If you go too near, the ice will give way with you. I'll see if I can get him out."
By this time Tommy's head was to be seen above the water. He knew how to swim, but one cannot do much swimming in ice-cold water, and with skates on one's feet, besides wearing heavy clothing. Poor Tommy was in a sad plight.
"Help! Help!" he called.
"Yes, I'll help you as soon as I can," answered the man. "I must get a plank to put down on the ice, though, so it will bear my weight."
A plank on thin ice acts just as Bert's snowshoes did on the snow, it holds a person up, keeping him from breaking through.
While the man was running toward the piles of lumber in Mr. Bobbsey's yard, which was on the edge of the lake, Freddie and Johnnie, not stopping to take off their skates, ran toward the office where Freddie's father was.
By this time the men in the lumber office, looking out on the lake, had seen that something was wrong. And they guessed what
