The piano, then, one hundred and fifty-seven years after its invention, in spite of its great cost, has become the leading musical instrument of Christendom. England produces thirty thousand every year; the United States, twenty-five thousand; France, fifteen thousand; Germany, perhaps ten thousand; and all other countries, ten thousand; making a total of ninety thousand, or four hundred and twenty-two for every working-day. It is computed, that an average piano is the result of one hundred and twenty days' work; and, consequently, there must be at least fifty thousand men employed in the business. And it is only within a few years that the making of these noble instruments has been done on anything like the present scale. Messrs. Broadwood, of London, who have made in all one hundred and twenty-nine thousand pianos, only begin to count at the year 1780; and in the United States there were scarcely fifty pianos a year made fifty years ago. We need scarcely say that the production of music for the piano has kept pace with the advance of the instrument. Dr. Burney mentions, in his History of Music (Vol. IV. p. 664), that when he came to London in 1744, "Handel's Harpsichord Lessons and Organ Concertos, and the two First Books of Scarletti's Lessons, were all the good music for keyed instruments at that time in the nation." We have at this moment before us the catalogue of music sold by one house in Boston, Oliver Ditson & Co. It is a closely printed volume of three hundred and sixty pages, and contains the titles of about thirty-three thousand pieces of music, designed to be performed, wholly or partly, on the piano. By far the greater number are piano music pure and simple. It is not a very rare occurrence for a new piece to have a sale of one hundred thousand copies in the United States. A composer who can produce the kind of music that pleases the greatest number, may derive a revenue from his art ten times greater than Mozart or Beethoven enjoyed in their most prosperous time. There are trifling waltzes and songs upon the list of Messrs. Ditson, which have yielded more profit than Mozart received for "Don Giovanni" and "The Magic Flute" together. We learn from the catalogue just mentioned, that the composers of music have an advantage over the authors of books, in being always able to secure a publisher for their productions. Messrs. Ditson announce that they are ready and willing to publish any piece of music by any composer on the following easy conditions: "Three dollars per page for engraving; two dollars and a half per hundred sheets of paper; and one dollar and a quarter per hundred pages for printing." At the same time they frankly notify ambitious teachers, that "not one piece in ten pays the cost of getting up, and not one in fifty proves a success."