86 THE ROLLER CANARY 
closed beak, otherwise they are not nice. In Bass Roll 
the vowels and consonants should be equally balanced 
—i.e., they should be emphasized with the same force; 
the result will be a vigorous purring, firmly, evenly, 
closely knit together. 
What there was of Knorre (Bass Roll sung on the o) 
fifteen years ago or so was good. At that time Knorre 
(Bass Roll sung on a) was in favour and had good points 
awarded, but, being shallow, flat and harsh in tonality 
it was of little value. 
SONG OF EXCEPTIONAL BEAUTY 
On the other hand we have now developed out of 
Bass Roll a Hollow Bass of exceptional beauty; the 
rumbling consonants are in this tour relegated to the 
background, the vowel sound comes out plainer, and 
one hears at the same time a further ti or 1 sounding out 
a fourth, a fifth, or an octave higher. One therefore has 
to do with a double or two-tone Bass (Knorre). The 
effect is very pleasing, well balanced throughout, a very 
beautiful harmonious combination. 
Another grand example of the Bass type is when 
the bird starts with a good Bass Roll, and then, passing 
on to a yet deeper Hollow Bass, finishes off by widening 
out into Gluck-like form. In such a series three kinds 
of Bass are heard; the last-named is Gluck Bass (Gluck- 
Knorre), in which one can detect a soft I. 
Koller Bass predominates in the deepest hollow; the 
Knorre sound (rrr) is intermingled with a hollow o and u 
is a Schockel, tremolo form. If the Knorre sound lies 
quite in the background, the vowel sounds u or o, 
gushing forth in a vibrating, shaking Hollow; we should 
