Ocular, known or seen by the eye.
Demonstration, the act of proving with certainty.
In how many divisions may musical instruments be arranged?
There are three kinds, namely, wind instruments, as the trumpet, and the organ;—stringed instruments, as the harp or lyre, violin, &c.; and instruments of concussion, in which the sound is produced by striking a sonorous body, as for instance the drum, bells, &c.
Which of these three kinds was the first invented?
It is impossible, at the present day, to decide which; but it is most probable that instruments with strings were the last invented of the three kinds; and it is most likely, that of those in which sound is produced by the application of wind, the trumpet or horn was first used. This instrument, in its rudest form, was ready fashioned to the hand of man; the horn of a ram or of an ox, or some of the larger kinds of sea-shells, were soon discovered to possess the power of producing sound, by being blown into through a small hole at the pointed end.
What improvement in this instrument would naturally follow?
Mankind having discovered the property possessed by a hollow tube of producing a certain sound, soon found that the note varied according to the length and capacity of the tube. A much greater improvement soon after took place; it was discovered that one tube answered the purpose of many by boring holes in the course of its length, and producing various musical sounds by stopping with the fingers certain of these holes. Most of our modern wind instruments are but improvements on the ancient inventions.
Tube, a pipe; a long hollow body.