The new instrument had been at the Exposition for six weeks without attracting serious attention. But Mr. Hubbard arranged that the judges should examine it for a few minutes on the Sunday afternoon following Bell’s arrival. The afternoon, however, was very warm, and there were a great many exhibits for the judges to inspect. There was the first grain-binder, and the earliest crude electric light, and Elisha Gray’s musical telegraph, and exhibits of printing telegraphs. It was seven o’clock when the judges reached Bell’s table, and they were tired and hungry. One of the judges picked up the receiver, looked at it, and put it back on the table. The others laughed and joked as they started to go by. Then they stopped short. A man had come up to the table, with a crowd of attendants at his heels. He said to the young man at the table, “Professor Bell, I am delighted to see you again.” The new arrival was the Emperor Dom Pedro of Brazil, who had once visited Bell’s school for deaf-mutes in Boston. The Emperor said he would like to test Bell’s new machine. With the judges, a group of famous scientific men, and the Emperor’s suite for audience, Bell went to the transmitter at the other end of the wire, while Dom Pedro put the receiver to his ear. There was a moment’s pause, and then the Emperor threw back his head, exclaiming, “_My God--it talks!_” The Emperor put down the receiver. Joseph Henry, who had encouraged Bell in Washington, picked it up. He too heard Bell’s own words coming from the disc. He too showed his amazement. “This comes nearer to overthrowing the doctrine of the conservation of energy,” said he, “than anything I ever saw.” After him came Sir William Thomson, later known as Lord Kelvin. He had been the engineer of the first Atlantic Cable. He listened intently. “Yes,” said he at last, “it does speak. It is the most wonderful thing I have seen in America!” Until ten o’clock that night the judges spoke into the transmitter and listened at the receiver of Bell’s instrument. Next morning it was given a place of honor, and every one begged for a chance to examine it. It became the most wonderful exhibit of the Centennial, and the judges gave Bell their Certificate of Award. Nothing more opportune could possibly have happened for the inventor.