THE ROLLER CANARY 89 
charming effect. The best quality tour is sung deep on 
the vowel u. 
These Water Rolls are therefore precious jewels in 
the storehouse of our songsters, and it is only birds 
of the deepest strains which are able to perform 
such without detriment to the other parts of their 
song. 
Water Rolls are of the greatest importance in the 
furtherance of the development of Canary song; the 
uncommonly deep pitch is inexhaustible for the 
production of fresh forms and variations. 
Like the Bass tours, they are a fertile source of tone, 
deep, fundamental, parent tours, and really deserve to 
stand on a level for points with Hollow Roll and Knorre. 
In their shallow and weaker forms they may certainly 
also be quite as dangerous. 
KOLLER 
The ground tones of Koller are o, u, Ui, 6, 61, au, eu. 
The consonants are bl, gw, kw, r, 1. The syllables 
sung in Koller are brloiroiluilui—briilluillii, bloiroirui 
—blrauiroiloi, gwlrairoirui—kwlreuiliullii. 
Koller may be sung in two styles—namely, as Hollow 
Koller and Water Koller. The Hollow Koller style 
gives the impression of relationship with Hollow Roll, 
the Water Koller style leans towards the Water Roll, 
Knorre, and Gluck family. 
A characteristic of Koller is the sound ringing 
out in each beat, while alternating deep down we have 
the sounds u, 6, li, au, 00, or eu rocked in (schockelled) 
in combination with the consonants 1, h, or rl. The 
effect produced is a series of syllables, succession of beats, 
‘6s 9 
i 
