Down the hill thundered the fire engine, the man on the back step keeping the whistle going. Behind the steamer came the powerful automobile containing Ned, Bob and Jerry, and after them came a crowd of men and boys, while a car or two, not having the speed advantage of the motor boys’ vehicle, trailed after. “If they make the turn into Water street, a block above the river, they’ll be safe,” said Ned to his tall chum beside him in the seat. “The hill isn’t so steep there. But if they keep on down past Water street----” “It’s into the water for them!” grimly finished Jerry Hopkins. “We’ll try to stop them before they get there.” He gave the auto a little more gasoline, and it leaped forward. At the same moment Bob yelled: “There it is! See the blaze!” He pointed off to the left, and there a glare in the sky, which increased in brightness as the boys looked, could be observed. “One of the tenements over in Frogtown!” exclaimed Ned, naming a poor section of Cresville where lived a number of foreigners who worked in the various factories. Of late a number of new industries had sprung up in the place, and the foreigners, who made up a large share of the workmen, were quartered in long rows of tenement houses, on the outskirts of Cresville, the place being styled “Frogtown,” because built on filled land, where once had been a frog-infested pond. “If those shacks get to going there’ll be some fire,” murmured Ned. “And they’ll get a good start if the engine doesn’t soon reach the place.” “Some one ought to send in another alarm, and bring out the other engine,” added Bob. “This one won’t be much good if it goes to smash.” “We’ve no time to send in alarms now,” muttered Jerry. “Let some one else do that. We’ve got to stop those horses if we can!” Ned and Bob clung to the sides of the car. This was in the lead now, and nothing was between their automobile and the swaying, rumbling engine. Suddenly Ned gave a cry and pointed to something. “What is it?” asked Jerry. “Another fire?” “Look at that old man! Right in the path of the engine! The horses’ll be on him in a minute!” “That’s right!” chimed in Bob, from the rear seat. “Hi there! Get out the way!” he yelled. “Don’t you see the engine?” Certainly the man at the side of the road, standing in the full glare of an arc electric light, ought to have heard the rattle of the runaway engine, even if he did not see it, though the place was well illuminated, and there was then no other vehicle in sight, save the automobile of the motor boys. There was something familiar about the odd figure, but neither Ned, Bob nor Jerry had time just then to look closely enough to make out who it was. “What’s he doing?” asked Jerry, as he skillfully guided his machine and turned on a little more speed, for he was nearing the engine, and wanted to be in a position to stop the runaway horses if he could.