"You have seen for yourselves and gan therefore judge how marvellously lighd this medal is," continued the professor when the plate had been handed back to him; "bud ids _sdrength_ you musd dake my word for, as I have no means ad hand do illusdrade id. Ids sdrength is as wonderful as ids lighdness, being--zo var as I have had obbordunidy do desd id-- exactly one hundred dimes thad of the besd sdeel." "If that be the case, professor, then I should say you have solved the problem of aerial navigation," remarked the colonel. "But you spoke of having also discovered a new power. What is it?" The professor once more instituted a search in his pockets, and at length produced a small paper packet, which, on being opened, was found to contain about a table-spoonful of green metallic-looking crystals. "There id is," he said, handing the packet to the colonel for inspection. "Um!" ejaculated the colonel, turning the crystals over slowly with his finger. "Quite new to me; I don't recognise them at all. And what is the nature of the power derivable from these crystals?" "Dreated in one way they give off elegdricidy; dreated in another way they yield an exbansive gas, which may be subsdiduded for either gunbowder or sdeam," answered the professor. "Are they explosive, then?" asked the colonel. "Nod in their bresend form. You mighd doss all those crysdals indo the fire with imbunidy; but bowder them and mix indo a baste with a zerdain acid, and whad you now hold in your hand would develop exblosive bower enough to demolish this building," was the quiet reply. The professor's little audience looked at him incredulously; a look to which he responded by saying: "Id is quide drue, I assure you," in such convincing tones as left no room for further doubt. They knew the professor well; knew him to be quite incapable of the slightest attempt at deception or exaggeration. "Then, if I have understood you aright, you will construct your aerial ship of your new metal, and apply your new power to give motion to her machinery?" said the colonel. "Yes. Thad is do say, I _would_ if I bossessed the means do build such a ship as I have described. Bud I am a scientist, and therefore boor. Never mind; I have no doubt thad, when I make my discoveries known, I shall find some wealthy man who, for the sake of science, will find der money," said the professor hopefully. "How much would it cost to build an aerial ship such as you have been speaking of?" asked the baronet. "Oh! I cannod say. Nod zo very much. Berhabs a hundred thousandt bounds," was the reply. "Phew! That's rather `steep,' as the Yankees say. But--`a fool and his money are soon parted'--if you are convinced that your scheme is really practicable, professor, I will find the needful," remarked the baronet.