As has been intimated above, the history of the French horn is short. There is but a slight analogy between it and the _cor de chasse_ of the Middle Ages, an instrument that possessed but few tones. The genuine French horn made its appearance in the first half of the seventeenth century, and the stages of its development may be regarded as centennial. In the eighteenth century was added the crook principle, in the nineteenth, the valve system. These improvements were attendant upon those made upon trumpets. Like the trumpet, the "natural" horn was conducive to purity of tone, the chromatic horn to greater practicability without material loss of purity. The family of bugles belong more properly to the subject of military bands, but a word is due to their evolution on account of the orchestral importance of one of their members--the bass tuba. The bugle-horn, also known as the sax-horn, is constructed on acoustic principles diametrically opposed to those of the trombe family in that the bore is wider and the tube shorter, whereby the principle of obtaining harmonics is reversed. The date of Beethoven's birth signalized the first application of key mechanism to wood instruments. Simultaneously, experiments were made upon the now obsolete brass Zinken. The new instrument was called _bugle à clefs_, and was the forerunner of a group of different sized opheicleides, of which the lowest supplanted the sixteenth century Serpent. Subsequently the opheicleide itself was superseded by the bass tuba, a more noble instrument of the same general family. V. The evolution of instruments of percussion requires but brief mention. Sound-producing apparatus devoid of definite pitch belongs to the initial attempts of primitive men to assist vocal expression of emotional feeling, to accompany religious orgies, or to encourage their warriors on the march. The modern orchestra includes the best of these primitive species, transformed into perfected types of genuine artistic value, and has also drawn into requisition various instruments originating in countries that are far apart. Most commonly used are the bass-drum, the cymbals, and the triangle. The family of drums further includes the long side-drum and the small military drum. With the cymbals and triangle belong the tam-tam or Chinese gong, the Oriental and Spanish tambourine, the Spanish and Neapolitan castanets, and the Turkish crescent or bell-rattle. The use of all such instruments is, of course, the exception rather than the rule. Their mission is primarily to suggest "local" coloring or to emphasize rhythm for dancing.