There were three "bugs" lighted over the engine. Ernest and Gustav were both smoking violently. Dick was chewing gum. Elsa and Charley said nothing but watched every movement on the part of the men. "Come here, Felicia," said Roger, biting at his cold pipe. "You see this little valve? All right. Now, as I've told you many times, I hope that when you turn this, that the sun which shone to-day will turn the big fly wheel round. When I give the wheel a twist, you turn the valve clear over." "Yes, Roger," replied Felicia, her little fingers quivering as she grasped the valve. "Now!" exclaimed Roger, tugging at the fly-wheel. There was a moment's breathless silence. Then very slowly and sedately, the fly wheel began to revolve, gathered speed and shortly was chugging away steadily. A little cheer rose from Roger's audience. He grinned. "Now Ern, let's throw in the pump." A belt, connecting the engine with the pump outside, was quickly slipped in place. The engine slowed down. But a moment later the sound of water pouring over the condenser pipes was heard above the chugging of the engine and pump. Gustav and Ernest fell on each other's necks. "It works!" squealed Felicia. "It works and I helped make it, I did." Peter, his head as far in at one of the windows as a very short neck would carry it, brayed. Roger watched the pressure gauge and scratched his head thoughtfully. Charley and Felicia slipped outside to inspect the pump, and Charley called: "Does anybody smell anything?" At the same moment Felicia shrieked. "Oh! oh, Roger! There's a terrible leak out here!" Roger shut off the engine and followed by the others, he darted to the condenser. The odor of sulphur dioxide filled the night. "By Jove, it's big enough to lose my charge!" groaned Roger. "Bring bugs, everybody." Felicia, "bug" and oil can in hand, was running over the pipes at the top before the others had arrived. "Here it is, Roger! Oh, an awful one. There!" The leak was in a pipe joint at the top of the stack. The odor grew almost unbearable. For half an hour the men wrestled with it, turn about, and at last succeeded in stopping it. Other minor leaks occurred but all were located and controlled. Finally Roger announced all safe and lighted his pipe. In the flash of the match, his face showed tense and dripping with sweat, his eyes bloodshot from the gas fumes. "Darn the leaks!" exclaimed Elsa. "Well, it's what we'll have to expect as long as I can't afford to buy bent pipe or an acetylene welding outfit," said Roger. "But after all, the leaks are the least of my troubles." "What is troubling you?" asked Charley quickly. "There isn't as much power there as my calculations had indicated there would be." "I told you that you were running pretty close on your absorption area," exclaimed Ernest. "You see your temperature readings have been lower right along down here than that table we had up in the laboratory for this region."