Mark sprang out of bed and with Jack rushed to the window, for their room was filled with thick smoke. They could see the dull glare of flames, which every moment were becoming brighter.
The next instant a loud explosion shook the building. It swayed and seemed likely to topple over. Outside the boys could hear excited shouts and the puffing and whistling of fire engines.
"Quick! Run!" yelled Mark. He opened the door leading into the corridor, but was driven back by a rush of flames and smoke that almost stifled him.
"We must try the fire escape!" shouted Mark.
"Don't forget the valise with the tools;" exclaimed Jack, and Mark hastened to where he had placed it under the bed.
Then the two boys rushed to the balcony on which their front windows opened, and whence the fire escapes led down to the streets. The lads had only time to slip on their coats, trousers, shoes and caps.
As they were preparing to clamber down the iron ladders they heard someone on the balcony next to them shout:
"Here, you boys! Stop! I want you!"