As Ernest had remarked, the rainy season generally ended in violent thunderstorms, which lasted for five or six days. The whole heavens were then illumined by lightning, followed by peals of thunder as though the starry vault were crashing in, peals which re-echoed from a thousand points along the shore.
It was on the 17th of August that these storms were announced by a rising of the temperature, an increasing heaviness of the atmosphere, and a drifting up in the north-west of livid clouds, denoting high electric tension.
Rock Castle, from the shelter of its dome of rock, set wind and rain at defiance. There was nothing to be feared there from the lightning, which is so dangerous in open country or among trees, to which the electric fluid is easily attracted.
The next day but one, in the evening, the skies were rent by the most terrible ball of fire that had fallen yet. All gathered in the library sprang to their feet at the noise of the dry and rending peal of thunder, which went rolling on and on through the upper zones of the air.
Then, after a minute's interval, dead silence reigned outside.
The bolt had unquestionably fallen not far from Rock Castle.
At this moment the report of an explosion was heard.
"What is that?" cried Jack.
"It is not thunder," said M. Zermatt.
"Certainly not," said Mr. Wolston, who had come to the window.