Kathleen Schlesinger, 1911 Encyclopædia Britannica, Volume 21… (1911)
“ The beak mouthpiece is exactly like that of the other clarinets but of larger size, and it is furnished with a single or beating reed. There are 13 keys and 2 rings on the tube, and the fingering is the same as for the B flat clarinet except for the eight highest semitones. ”
