Claire made the calculation. The result was 4080 meters.
“The flash of lightning was 4080 meters away; we are more than a league from the storm-cloud,” said her uncle.
“How easy that is!” exclaimed Emile. “You count one, two, three, four, and without moving you know how far away the thunderbolt has just fallen.”
“The longer the time between the flash and the noise, the farther away is the cloud. When the report comes at the same time as the flash, the explosion is quite near. Jules knows that well since the day of the storm in the pine woods.”
“I have heard that there is no longer any danger after the lightning is seen,” said Claire.
“A thunderbolt is as rapid as light. An electric explosion is, therefore, ended as soon as the flash appears, and all danger is then passed; for the thunder, however loud it may be, can do no harm.”
CHAPTER XLIII
THE EXPERIMENT WITH THE BOTTLE OF COLD WATER
UNCLE PAUL had rightly said, the evening before, that clouds are nothing but fog floating high in the air instead of spreading over the earth; but he had not said what fogs are composed of and how formed. So the next day he continued his talk on clouds.
“When Mother Ambroisine hangs the clothes she has just washed on the line, what does she do it for? To dry the linen, to free it from the water with which it is saturated. Well, what becomes of this water, if you please?”