"In my opinion, the trombone is the true head of the family of wind instruments, which I have named the 'epic' one. It possesses nobility and grandeur to the highest degree; it has all the serious and powerful tones of sublime musical poetry, from religious, calm and imposing accents to savage, orgiastic outburst. Directed by the will of the master, the trombones can chant like a choir of priests, threaten, utter gloomy sighs, a mournful lament, or a bright hymn of glory; they can break forth into awe-inspiring cries and awaken the dead or doom the living with their fearful voices."
From Introducing the Alto Clef for Trombone by Fink:
Many teachers believe that the alto clef must be read as the alto clef and not as an interval transposition related to the treble clef. Other teachers believe that transposition by interval is all right at the beginning and that in time the student will naturally and gradually change to the reading of the alto clef as a clef, not as a transposition. Therefore the end result will be the same no matter which method is used in the beginning.