DRUM, a musical instrument of percussion, which is supposed to have been introduced into Europe from the East by the Moors or after the Crusades. In certain forms, however, it was known in Europe in classical times. The Greek and Roman tympanum seems from descriptions and pictorial representations to have included not only tambourines but kettledrums of a small size, or at least instruments convex on one side like the kettledrum. The instrument designated in Scripture a timbrel (Heb. toph) was undoubtedly a kind of tambourine, such as might be conveniently played by females. In India and Egypt the use of drums in a considerable variety of forms may be traced back to the earliest historic times. The tam-tam or tom-tom of India, a cylindrical drum of some size beaten with the fingers, had its counterpart in Egypt at least as early as 1600 B.C. Among savage races, whose music has not risen above the primitive or percussive stage, the drum is naturally the chief, and in many cases the sole instrument employed. Three principal forms of drum are in general use in the modem orchestra,—the common or side drum, the base or Turkish drum, and the kettledrum. The first is composed of a cylinder of wood, or, more generally, of metal, covered at each end with vellum or parchment, the tension of which is regulated by strings. As its name indicates, it is worn at the side of the performer, who beats upon the upper end with two sticks. Its distinctive though not its exclusive use is to accompany the military fife band. The base drum is a larger instrument of the same kind, the cylinder being composed of oak. It is beaten at both ends with drum-sticks furnished with leather pads. It is an important constituent of a full military band, but it is also employed in the orchestra, especially by more recent composers. The kettledrum is the most important form of the instrument in orchestral as distinct from military music. It is composed of a basin of brass or copper, almost hemispherical in shape, covered with vellum attached to an iron ring, and it is usually placed upon an iron tripod. By means of screws it is capable of being tuned within certain necessarily narrow limits. Kettledrums are always used in pairs, one being tuned to the key-note and the other to the fourth below. The music is usually written in the key of C; and the key in which it is to be played, if different, is indicated in words at the beginning of the passage. The three forms of drum just described are essential in every complete orchestra. In addition other percussive instruments, such as the gong and the tam-tam are sometimes introduced for the sake of particular effects.