ALC 
substitue for whites of eggs in clarifying 
sugar. 
ALBURNUM, denotes the white, soft 
substance that lies between the inner bark 
and the wood of trees, composed of layers 
of the former, which have not attained the 
solidity of the latter. Plants, after they 
have germinated, do not remain stationary, 
but are continually increasing in size. A 
tree, for instance, every season adds consi- 
derably to its bulk. The roots send forth 
new shoots, and the old ones become longer 
and thicker. The same increment takes 
place in the branches and the trunk. A 
new layer of wood, or rather of alburnum, 
is added annually to the tree in every part, 
just under the bark ; and the former layer 
of alburnum assumes the appearance of 
perfect wood. The alburnum is found in 
largest quantities in trees that are vigorous; 
though in such as languish and are sickly 
there is a great number of beds. In an oak 
six inches in diameter the alburnum is said 
to be nearly equal in bulk to the wood. 
ALCA, auk, in ornithology a genus of 
the order ofAnseres,in the Linnajan system, 
the characters of which are, that the bill is 
without teeth, short, compressed/ convex, 
frequently furrowed transversely; the infe- 
rior mandible is gibbous before the base; 
the nostrils are behind the bill ; and the feet 
have generally three toes. This genus com- 
prehends 12 species, of which we shall no- 
tice the following: A. torda, with four 
furrows on the bill, and a white line on each 
side running from the bill to the eyes. This 
is the alca of Clusius and Brisson ; the pin- 
guin' of Buffon ; and the razor-bill, auk, or 
murre of Pennant, Ray,Willughby, Albinus, 
Edwards, and Latham. This species weighs 
about 22-1 ounces; its length is about 18 
inches, and breadth 27. These birds, in 
company with the guillemot, appear in our 
seas in the beginning of February ; but do 
not settle in their breeding-places till they 
begin to lay, about the beginning of May. 
When they take possession of the ledges of 
the highest rocks that' hang over the sea, 
they sit close together, and in rows one 
above another, and form a very grotesque 
appearance. They lay only one egg at a 
time, which is of a large size, in proportion 
to that of the bird ; being three inches long, 
either white or of a pale sea-green, irregu- 
larly spotted with black : if this egg be de- 
stroyed, both the auk and the guillemot will 
lay another, and if this be taken, a third ; 
as they make no nest, they deposit the egg 
on the bare rock, poising it in such a manner 
ALC 
as no human art can effect, and fixing it by 
means of the viscous moisture that bedews 
its surface on its exclusion ; and though such 
multitudes of eggs are contiguous to each 
other, each bird distinguishes its own. These 
eggs serve as food to the inhabitants of the 
coasts which the birds frequent; and are 
procured with great hazard by persons let 
down with ropes, held by their companions, 
and who for want of stable'footing are some- 
times precipitated down the rocks, and pe- 
rish together. They are found in the north- 
ern parts of America, Europe, andAsia. They 
come to breed on the Ferroe islands, along 
the west of England, and on the Isle of Wight" 
where they add to the multitude of sea-fowl 
that inhabit the great rocks called the 
Needles. Their winter residence is not 
positively ascertained. As they cannot re- 
main on the sea in that season, and never 
appear on shore, nor retire to southern cli- 
mates, Edwards supposes that they pass the 
winter in the caverns of rocks, which open 
under water, but rise internally as much 
above the level of the flood as to admit a 
recess, and here, as he apprehends, they re- 
main torpid, and live upon their abundant 
fat. The pace of this bird is heavy and 
sluggish ; and its ordinary posture is that of 
swimming or floating on the water, or lying 
stretched on the rocks or on the ice. 
A. impennis, A. major of Bris'son, pen- 
guin of Ray, Martin, Edwards, &c. and 
great auk of Pennant and Latham, has its 
bill compressed and furrowed on both sides, 
and has an oval spot on each side before 
the eyes. Its length to the end of its toes 
is three feet; the bill to the comer of the 
mouth is 4J inches : the wings are so small 
as to be useless for flight; their length, from 
the tip of the longest quill-feathers to the 
first joint, being only 41 inches: and these 
birds are therefore observed by seamen 
never to wander beyond soundings, and by 
the sight of them they are able to ascertain 
the nearness of the land. They can scarcely 
even walk, and of course continue on the 
water, except in the time of breeding. Ac- 
cording to Mr. Martin, they breed on the 
isle of St. Kilda, appearing there in the be- 
ginning of May, and retiring in the middle 
of June. They lay one egg, six inches long, 
of a white colour ; and if the egg be taken 
away, no other is laid in the same season. 
Mr. Macaulay, in his history of St. Kilda, 
observes, that this bird does not visit that 
island annually, but sometimes keeps away 
for several years together; and that it lays 
its eggs close to the sea-mark, and is inca- 
