3 8 Of Feathers. 
tranfparent in common light, yet by looking at them 
againft the fun, found them to be tinged with a darkifh 
red, not at all refcmbling the curious greens and blues 
they exhibit. 
The changeable colour’d feathers of ducks, and fevera! 
other birds, he found upon examination with the micro- 
fcope to proceed from the fame caufes and textures. 
The beft way to apply one of thefe fmall downy 
fibres to the microfcope, is to pinch them between the 
nippers. 
Mr. Derham, in his defeription of the vanes of a 
flag feather of a goofe’s wing, obferves thefe two par¬ 
ticulars, i. That the exterior or narrow vanes bend 
downwards; the interior wider vanes upwards $ by 
which means they catch hold, and lie clofe to one ano¬ 
ther, when the wing is fpread, fo that not one feather 
may mifs its full force and impulfe, 2. That the very 
tips of thefe feathers are alfo neatly Hoped to a point, 
towards the outer part of the wing; the exterior vanes 
towards the body. 
The vane or web of a feather, confifts of fcveral 
laminae, which are thin, ftiff, and fornewhat of the na¬ 
ture of a thin quill; towards the fhaft of the feathers 
(efpecially in flag feathers of the wing) thofe laminae 
are broad, and of a femiciicular form, which ferves for 
flrength, and alfo for fhutting thefe plates clofe to one 
another, when impulfes are made upon the air. To¬ 
wards the outer part of the vane, tnefe laminae grow 
flender and taper; on their under fide they are thin 
and fmooth, but are parted mto two hairy edges on the 
upper; each fide having a different fort of hairs lami¬ 
nated or broad at bottom, and flender and bearded above 
the other half. k 
a The 
