Mr. O'CONNELL. It is simply by relation to what is called the tracker board. This roll goes over a tracker board in which there are little holes. Each hole in the tracker board is connected with a little tube which carries the air through a bellows and to a device which strikes a hammer. As this roll goes over the tracker board of the instrument, when it strikes a hole corresponding to any particular one of those slits there is an ingress of air, because there is a vacuum underneath. That little tube is connected with a hammer which strikes the note A, B, C, and so forth, whatever it might be. They are differently arranged in different rolls. The roll that will play in one instrument will not play in another; and you can see, gentlemen, that there is a different-sized roll, different-sized slits [exhibiting sample rolls] notwithstanding that they are both the same piece of music, composed by Mr. Sousa. [Laughter.] Senator SMOOT. In looking at those two rolls, there is no question but what anybody can tell that they are the same piece of music. Mr. O'CONNELL. But look at the difference across---- Senator SMOOT. That is only as to the size. You can take that same sheet of music that Mr. Sousa exhibited and have it four inches wide or you can have it eight inches wide, and it would be just the same music. Mr. O'CONNELL. But can anybody tell me, if you please, sir, or will anybody tell us, what those notes are? Senator SMOOT. That is the question that I asked you. Mr. BOWKER. I can, by taking a scale corresponding to that instrument and putting it on the paper. By doing that you can tell what the note is. Mr. WALKER. I was counsel in the Apollo case, and the question whether those rolls could be read by inspection was litigated at great expense in that case, and the circuit court of appeals for the second circuit decided, a week ago last Friday, that the overwhelming preponderance of the evidence was that they could not be read. Mr. WEBB. And further, that that is not a copy of the music from which it is taken. Mr. WALKER. They so decided. Judge Colt decided in 1888 that these perforated rolls are not copies of music filed in the office of the Librarian of Congress. That decision was always acquiesced in until the Æolian Company invented its ingenious scheme to monopolize the business of mechanical musical instruments; and in pursuance of that event they endeavored to secure from the circuit court of appeals in the southern district of New York a reversal of Judge Colt's decision. After years of litigation the circuit court of appeals for the second circuit affirmed Judge Colt's decision, and held that these do not infringe the copyright on the sheet music, and, as the foundation for that holding, they stated the overwhelming preponderance of evidence was that they could not be read by anybody; and they stated for that reason that they were not copies, and were not infringements.