Learning that the Centennial judges had arranged for a special inspection of certain telegraph and electrical apparatus on Sunday, June 25, when only those specially invited would be present and the building would be comparatively quiet, Mr. Hubbard sent a telegram requesting Graham Bell to arrive in Philadelphia not later than Sunday morning. But the class examinations were of far more importance just then than any explanation he could give the judges. So Graham Bell decided not to go. Then he received a message that Mr. Hubbard's daughter, Mabel (who a year later became Mrs. Bell), was leaving for Philadelphia, and hurried to the station in Boston to bid her good-bye. Mabel was as anxious as was her father to have Graham Bell explain his invention to the judges at the Centennial, and when she found that his sense of duty to his classes outweighed her influence, woman-like she burst into tears just as the train started. This was more than Graham Bell could stand, so he jumped aboard the moving train and with neither ticket nor baggage went through to Philadelphia.
As the weather was excessively hot in Philadelphia on Saturday evening Mr. Hubbard went to his Washington home 'tired out.' Sunday was another hot day, and after the judges had completed their inspection of all the other exhibits, and 'when it was already late, and the allotted time very nearly exhausted,' and while 'it was very warm, and signs of impatience were becoming manifest on the part of some of those present,' Graham Bell extended an invitation to the judges to inspect his telephones.
After some delay and discussion the judges proceeded to the Massachusetts section, where the apparatus was exhibited on a small table in a narrow space 'between the stairway and the wall.' Accompanying the judges were a large number of distinguished visitors, including the emperor of Brazil. Fortunately, but a short time before, the emperor had visited Graham Bell's school in Boston and had become interested in the method of instruction and also in the telephone. When Graham Bell saw that the emperor was with the judges he did not dream that his brief interview would be recalled. But his majesty cordially greeted him and spoke so enthusiastically about the telephone, that, tired as the judges were, they concluded to investigate thoroughly its merits. And from that moment the future of the telephone was assured.
Chief among the judges was Sir William Thomson (now Lord Kelvin), then and now the world's leading electrical scientist. He listened at the receiver, while Graham Bell's assistant talked into the transmitter. Sir William then went to the distant transmitter and repeated certain lines from Hamlet, which were heard as the receiver passed from one visitor to another. Forgotten was all thought of fatigue, of heat and discomfort, and nearly every visitor was glad of the opportunity of going to the end of the line and talking into that crude transmitter.
