“Very well: now examine what takes place; on propelling forward your second pellet, you condense the air which is enclosed between the two, until its elastic force becomes so great as to overcome the friction of the first pellet; thus released, the air expands with considerable force, and imparts a rapid motion to the pellet.” “I have frequently heard of the air-gun,” said Louisa; “I suppose it depends upon a similar principle.” “It does; and it affords a very striking example of the surprising force which air is capable of exerting, when condensed to a considerable degree; for, by means of this instrument, bullets may be propelled with a force very nearly equal to that of gunpowder.” “It is a curious fact,” observed the vicar, “that although the air-pump is a modern invention, yet the air-gun, which is so nearly allied to it in the construction of its valves and condensing syringe, should have existed long antecedent to it; for it is recorded that an air-gun was made for Henry IV. by Marin, of Lisieux, in Normandy, as early as 1408; and another was preserved in the armoury at Schmetau, bearing the date of 1474.” “But the air-gun of the present day,” said Mr. Seymour, “is very different from that which was formerly made, and which, like the pop-gun, discharged but one bullet, and that after a long and tedious process of condensation, while it is now made to discharge five or six without any visible variation of force, and will even act upon a dozen, but with less effect.” “I feel very curious to learn something more about this air-gun,” said Tom. “There is a reservoir for the condensed air,” replied Mr. Seymour, “which is secured by a nicely constructed valve, and which is made to open by pulling the trigger of the gun, so that a portion only of the air is disengaged, which, rushing into the barrel, gives motion to the ball.” “But how is the condensed air introduced into the reservoir?” asked Tom. “By means of a condensing syringe,” replied his father; “but I will take an opportunity of exhibiting the instrument in operation.” The reader will be pleased to recollect that the major agreed to pay a passing visit to the vicarage; it now becomes our duty to record what happened upon that memorable occasion; and we, perhaps, cannot better represent the nature of the discussion that took place than by relating the account as it was given by the belligerent parties themselves in conversation with Mr. Seymour. “Well, gentlemen,” said Mr. Seymour, “is it peace or war? I trust you have amicably adjusted all your differences.” “Upon my word,” answered the vicar, “I have just reason to complain of the major’s unjustifiable scepticism upon points that are perfectly unquestionable.” “You continue then to smart under the major’s stinging criticisms, ‘_majore sub hoste_.’ There is a Latin pun for your consolation,” said Mr. Seymour.