I know it now, though I couldn't believe my ears at the time.

The light he scared the Indians with must have been an electric flash, worked by a storage battery.

But it is all so incredible! I wonder if I am really awake or still dreaming ?" To assure himself on this point Cabot went to the light, and, as he did so, came upon another surprise greater than any that had preceded it.
He had wondered at the comfortable temperature of the room, for there was nowhere a fire to be seen, and the blizzard still howled outside with unabated fury.

Now, on drawing near to the lamp, he found himself also approaching some heretofore unobserved source of heat, which he discovered to be a drum of sheet iron.

It stood by itself, unconnected with any chimney, and apparently had no receptacle for any form of fuel, solid, liquid, or gaseous.
"A Balfour electric heater," murmured Cabot, in an awe-stricken tone, "and I didn't even know they had been perfected.