“Since sound radiates in all directions, it follows that, if such radiation be prevented by confining it in tubes, it may be carried to a great distance with very little diminution of its effect; and hence the use and application of those trumpets, or tin speaking-pipes, which are now commonly used for conveying intelligence from one part of a house to another. The trumpet used by deaf persons acts on the same principle; but as the voice enters the trumpet at the large instead of the small end of the instrument, it is not so much confined, nor is the sound so much increased.” “I believe,” said Mrs. Seymour; “that the experiment exhibited some time since in London under the title of the _Invisible Girl_, and which excited such general curiosity, was discovered to depend upon an arrangement of this kind.” “I expected that you would allude to that exhibition,” said Mr. Seymour; “and as I was anxious to provide my young pupils with some new amusement, as a reward for their industry, I have directed Tom Plank to construct the necessary apparatus for exhibiting and explaining the deception. On our return to the lodge, I have no doubt we shall find that every arrangement for the performance has been completed.” Miss Villers was now gratified by a view of the more interesting specimens in the geological temple. Mr. Seymour also explained the design of the pillars which had so greatly excited her curiosity. On the return of the party, Mr. Seymour found, as he had anticipated, that the necessary apparatus for the experiment of the “Invisible Girl!” had been duly arranged, and that Tom Plank was in attendance to afford any assistance which might be farther required. We shall proceed to describe all the visible mechanism, as it appeared to the children on entering Mr. Seymour’s study, and of which we here present the reader with a perspective sketch. [Illustration: Apparatus for Invisible Girl experiment.]