Edison contends that the phonograph will give the "acid test" of a voice, for it will record nothing more and nothing less than what is in the voice itself, and the record is unchangeable. In his judgment, operatic voices are not necessarily the most perfect ones, for, as he says: "the vocal cords of opera singers are always at the straining-point. They usually sing on roomy stages in large theaters with a large orchestra in front of them, and their voices must go out above all these instruments so as to be heard to the farthest limits of the house. Consequently, they are always doing their utmost and their vocal cords become adapted to heavy work only. People often wonder why their favorite operatic singers do not charm them as much in concert or through the phonograph as they did at the opera, but do not stop to think of the difference between the opera-house and the concert-hall or parlor. I don't mean to say a word of detraction in regard to operatic singers, for I have a great admiration for their wonderful art and for many of their voices, and a great number of them have now recognized the value of special effort to acquire the distinct art and technique of singing for the phonograph (which is a parlor instrument), and have made some really beautiful records." The writer was one day discussing with Edison the temperament of singers generally and the good opinion that each one usually has of his or her own voice irrespective of any artistic use he or she could make of it. He said: "I don't see what they have to be conceited about. The Almighty has given them a little piece of meat in their throats that differs slightly from the corresponding piece of meat in somebody else's throat. They can take no credit for that, but if they use their brains to interpret and perfect the use of what has been given them, they have accomplished something. What I want is voices that will stand the test of the phonograph and give permanent pleasure to people, irrespective of stage environment, or the press agent, or pleasing personality." This chapter could be extended to a great length in setting forth the results of Edison's deep study of music which he undertook solely for the purpose of bringing his latest achievement up to the high standard which he set for it so many years ago, but enough has been said to indicate the immense amount of work he has done and the trend of his ideas. That he has been able, amid the round of his multitudinous duties and work, which occupy his time and attention from sixteen to eighteen hours a day, to delve into the subject so profoundly and to evolve ideas that are confessedly awakening the musical world is sufficient to indicate that in spite of his years and herculean labors in the past he has not lost any of the vim or pertinacity that have so distinguished him in days gone by. XXVII EDISON'S WORK DURING THE WAR