As I have indicated by the table, the instruments with three valves have a chromatic compass of two octaves and a half; and extend, both as regards the cornet and alto, from F-sharp, below the staff, to C above the staff.* But it is not in every player’s power to perform with facility the whole of this compass.
It is therefore necessary, when writing for the above instruments, even even if it be a solo, not to attain the extreme limits of the scale indicated in the foregoing table. Often, bandmasters cause instruments to take flights of too elevated a nature. The consequence is that the artist loses the beautiful quality appertaining to the tone of his instrument; and ends by failing in the most simple passages, even when performed in the medium register. To avoid this evil, it is necessary to be continually practicing the instrument throughout its entire register; and to pay special attention to the chapter dedicated to the study of the various intervals.
The portion of the register in which it is the most easy to perform, commences at the low C and terminates at the G above the staff. One may easily ascend as high as B-flat; but the B-natural and the C ought but seldom to be made use of.
* The useable range of the trumpet has been greatly expended in contemporary usage.