As regards instruments of percussion, a kind of drum deserves special notice on account of the ingenuity evinced in its construction. The Mexicans called it _teponaztli_. They generally made it of a single block of very hard wood, somewhat oblong square in shape, which they hollowed, leaving at each end a solid piece about three or four inches in thickness, and at its upper side a kind of sound-board about a quarter of an inch in thickness. In this sound-board, if it may be called so, they made three incisions; namely, two running parallel some distance lengthwise of the drum, and a third running across from one of these to the other just in the centre. By this means they obtained two vibrating tongues of wood which, when beaten with a stick, produced sounds as clearly defined as are those of our kettle drums. By making one of the tongues thinner than the other they ensured two different sounds, the pitch of which they were enabled to regulate by shaving off more or less of the wood. The bottom of the drum they cut almost entirely open. The traveller, M. Nebel, was told by archæologists in Mexico that these instruments always contained the interval of a third, but on examining several specimens which he saw in museums he found some in which the two sounds stood towards each other in the relation of a fourth; while in others they constituted a fifth, in others a sixth, and in some even an octave. This is noteworthy in so far as it points to a conformity with our diatonic series of intervals, excepting the seventh. The _teponaztli_ was generally carved with various fanciful and ingenious designs. It was beaten with two drumsticks covered at the end with an elastic gum, called _ule_, which was obtained from the milky juice extracted from the ule-tree. Some of these drums were small enough to be carried on a string or strap suspended round the neck of the player; others, again, measured upwards of 5 feet in length, and their sound was so powerful that it could be heard at a distance of three miles. In some rare instances a specimen of the _teponaztli_ is still preserved by the Indians in Mexico, especially among tribes who have been comparatively but little affected by intercourse with their European aggressors. Herr Heller saw such an instrument in the hands of the Indians of Huatusco――a village near Mirador in the Tierra Templada, or temperate region, occupying the slopes of the Cordilleras. Its sound is described as so very loud as to be distinctly audible at an incredibly great distance. This circumstance, which has been noticed by several travellers, may perhaps be owing in some measure to the condition of the atmosphere in Mexico. Instruments of percussion constructed on a principle more or less similar to the _teponaztli_ were in use in several other parts of America, as well as in Mexico.