als 
3, Density or Compactness of Flue. —Among a number of feathers 
great variation is to be seen in the density of the flue, some being very 
nan or open, while others are very dense or compact. Other characters 
being equal, a dense, compact feather is much more valuable than a thin 
one. The density of the flue depends upon three factors: (1) closeness of 
the barbs, (2) closeness of the barbules, (3) the length of the barbules. 
The first two are correlated with one another, that is, the closer are the 
barbs on the shaft, the closer are the barbules on the barbs. One can 
readily see that the barbs are split off from the shaft much nearer together 
in some feathers than in others, and similarly with the barbules from the 
barbs. In most feathers the bar bs come off all in ‘he same vertical plane, 
but in some they come off so closely as to arrange themselves in an alter- 
nate manner down each side of the shaft, and thereby give the flue the 
appearance of being double; hence the term “ double- fiue,” or its mis- 
nomer “ double-floss,’” sometimes applied to such feathers, these being 
among the most valuable on account of their density. The length of the 
barbule is also an important character in determining the value of a 
feather, as the density or compactness of the flue is largely determined by 
it. Ab the present time length of barbule is probably more sought after 
by breeders than any other single feature, as without it no marked degree 
of density can be attained. 
The compactness of the flue should be equal throughout, that is, not 
more open or denser in some places than in others. The regularity pro- 
duces a great difference in the appearance of natural feathers, and is partly 
determined by the manner in which the plumes overlap one another in 
the process of growth. . 
4. Strength or Self-support of Flue: “Hard” and “ Woolly” Flue.—- 
The strength of the flue, by which is really meant the strength or stiff- 
ness of the individual barb, is a matter of great importance in estimating 
the value of a feather. Sometimes the flue of a feather will hang down 
from the shaft in a loose, pliant manner, the barbs having no self-support ; 
in others each barb will stand out at right angles from the shaft almost 
to its extreme tip. Such a feather is said to have a “ selft-supporting ’ 
flue, and, in general, the stronger, more self-supporting is the flue, the more 
valuable is the feather from the manufacturer’s point of view. In the best 
feathers, as already noted, the barbs come off practically at right angles 
from the shaft, and extend horizontally their entire length, thereby 
denoting great strength ; in poor feathers the barbs come off at an angle 
from the shaft and extend upwards instead of horizontally, or, being very 
weak, hang downwards in a limp manner. It is manifest that a barb ex- 
tending horizontally from the shaft gives full value.to the width of the 
plume, which is not the case where the barbs extend upwards or droop 
downwards. Independently of this feathers in which the barbs point up- 
wards instead of outwards are often narrow and of little value. In such 
plumes the flue as a whole is strong, but stiff and coarse. The term 
‘woolly ”’ is usually applied to a feather im which the flue is soft and non- 
supporting , and the term “hard” to ene in which the flue ig self- support- 
ing and firm. For manufacturing and dyeing purposes a hard feather is- 
oreatly preferred to a woolly one. 
5. Quality and Lustre.—Some feathers are quite harsh and coarse to 
handle, and are dull in appearance, while others are silky to the feel, and 
have a distinct gloss or lustre. The latter characters are those most de 
sirable, and are generally found in the plumes of birds which are well fed 
and in good condition. Silkiness, gloss, and lustre are sometimes com- 
bined wish a soft woolly flue which is very undesirable; the object aimed at 
is to combine strength of flue with quality and lustre. The feathers of 
wild birds are often very strong, but lacking in flexibility and lustre, 
