"Stand back with those lanterns, boys," he ordered.
I sniffed, expecting to smell illuminating-gas. Instead, a peculiar, sweetish odour pervaded the air. For a moment it made me think of a hospital operating-room.
"Ether," exclaimed Kennedy. "Stand back farther with those lights and hold them up from the floor."
For a moment he seemed to hesitate as if at loss what to do next. Should he open the door and let this highly inflammable gas out or should he wait patiently until the natural ventilation of the little office had dispelled it?
While he was debating he happened to glance out of the window and catch sight of a drug-store across the street.
"Walter," he said to me, "hurry across there and get all the saltpeter and sulphur the man has in the shop.
I lost no time in doing so. Kennedy dumped the two chemicals into a pan in the middle of the main office, about three-fifths saltpeter and two-fifths sulphur, I should say. Then he lighted it. The mass burned with a bright flame but without explosion. We could smell the suffocating fumes from it, and we retreated. For a moment or two we watched it curiously at a distance.
"That's very good extinguishing-powder," explained Craig as we sniffed at the odour. "It yields a large amount of carbon dioxide and sulphur dioxide. Now - before it gets any worse - I guess it's safe to open the door and let the ether out. You see this is as good a way as any to render safe a room full of inflammable vapour. Come, we'll wait outside the main office for a few minutes until the gases mix.
It seemed hours before Kennedy deemed it safe to enter the office again with a light. When we did so, we made a rush for the little cubby-hole of an office at the other end. On the floor was a little can of ether, evaporated of course, and beside it a small apparatus apparently used for producing electric sparks.
"So, that's how he does it," mused Kennedy, fingering the can contemplatively. "He lets the ether evaporate in a room for a while and then causes an explosion from a safe distance with this little electric spark. There's where your wire comes in, McCormick. Say, my man, you can switch on the lights from downstairs, now."