20. The Reformation produced great changes in the character of sacred music. Before that event took place, this part of religious worship was confined to a few fixed forms of texts, as in the mass, and this is still the case in the Roman Catholic Church; but the Protestants allow great variety both in the poetry and music. Luther's agency in the production of these changes was very considerable. During the seventeenth and eighteenth centuries, church music became continually more brilliant, and always more corrupted, by the intermixture of profane music. 21. In the sixteenth and seventeenth centuries, there grew up, at the courts of the European monarchs, the free chamber style, from which arose that which was afterwards used in the theatre. The opera, which originated with three young noblemen at Florence in 1594, has contributed especially to the splendor and variety of modern vocal music, the advancement of which is claimed particularly by the Italians, as that of the instrumental kind is claimed by the Germans and French. 22. The composition of music, and its execution either vocally or instrumentally, as well as the business of imparting a knowledge of it to others, are embraced in the employment of the musician; although it is seldom, that all these branches are practised by one and the same individual. Music is one of the fine arts, and, during the middle ages, was one of the branches of what was then considered a learned education. 23. Since the scientific revival of music, the art has had so many distinguished professors, that we will not even attempt to give a list of their names. Their number was increased, and the art greatly perfected, by the singing-schools, called _conservatories_, established especially in Italy, either at the public expense, or by the liberality of individuals. MUSICAL INSTRUMENT-MAKER. 1. This artist unites in his business some of the operations of the cabinet-maker, turner, and brazier. He also is dependent upon the wire-drawer, and the tanner and currier, for some of his materials. So great, however, is the number of musical instruments, and so different their nature and construction, that the business of making them is divided into several branches, all of which are never pursued, or carried on, by one person. But, without reference to the several divisions of this business, we will proceed to mention or describe the principal instruments which are now in most common use. 2. The _organ_ is the largest of all musical instruments, and, in its improved state, so complex that a mere description of it cannot be well understood. Nevertheless, we will endeavor to give the reader some idea of the general principles on which it is constructed.