“Ask him how,” said Fritz drily.

“Ah, you hope to puzzle me,” replied Jack, “but thanks to Mr. Wolston, I am too well up in physics to be easily driven off my perch, and therefore may safely take my turn in philosophising.”

“Well, we are listening.”

“The air, by means of the vapor it contains, absorbs electricity from terrestrial bodies, and so becomes a sort of reservoir of this invisible fluid.  All chemical combinations evolve electricity, the air collects it and stores it up in the clouds.  There, worshipful brother, your question is answered.”

“Good, go on.”

“Well, Willis, you must know, in the second place, the clouds are very good fellows, and share with each other the good things they possess.  When one cloud meets another, the one over-supplied with this fluid and the other in its normal state, there is an immediate interchange of courtesies, the negative electricity of the one is exchanged for the positive of the other.”

“There does not appear, however, to be much generosity in this transaction, since the surcharged cloud does not cede its superfluous abundance without a consideration.”

“It is very rarely that philanthropy amongst us goes much further,” remarked Fritz.

“No, everybody is not like Willis,” rejoined Jack, “who acts like a prince, and gives legs of mutton gratis to hyenas and tigers.  The discharges of electricity from one cloud to another are the flashes of lightning, and it is to be observed that the thunder is nothing more than the noise made by the fluid rushing through the air.”

“What, then, is the thunderbolt?”

“There is no such thing as what is popularly understood by the term thunderbolt.  The lightning itself, however, often does mischief.  This happens when the discharge, instead of being between two clouds in the air, takes place between a cloud and the ground—­a cloud surcharged with electricity understood.  Then all intervening objects are struck by the fluid.”

“There, however, you are wrong,” said Fritz.  “All objects are not struck; on the contrary, the fluid avoids some things and searches out others, even moving in a zig-zag direction to manifest these caprices; it often discharges itself on or into hard substances, and passes by those which are soft or feeble.”

“I might say this arose from a sentiment of generosity,” added Jack, “but I have other reasons to assign.”

“So much the better,” said Fritz, “as I should scarcely be satisfied with the first.”

“Well,” continued Jack, “lightning has its likings and dislikings.”

“Like men and women,” suggested Willis.

“It has a partiality for metal.”

“An affection that is not returned, however,” observed Fritz.

“If the fluid enters a room, for example, it runs along the bell wires, inspects the works of the clock, and sometimes has the audacity to pounce upon the money in your purse, even though a policeman should happen to be in the kitchen at the time.”