150 BLACK BILLED AUK. Ctass II, 
positing their egg on the bare rock; and though 
such multitudes lay contiguous, by a wonderful 
instinct each distinguishes its own. It is also 
matter of great amazement, that they fix their 
ege on the smooth rock, with so exact a ba- 
lance, as to secure it from rolling off; yet should 
it be removed, and then attempted to be re- 
placed by the human hand, it is extremely diffi- 
cult, if not impossible, to find its former equili- 
brium. 
The eggs are food to the inhabitants of the 
coasts they frequent; which they get with great 
hazard, being lowered from above by ropes, 
trusting to the strength of their companions, 
whose footing is often so unstable that they are 
forced down the precipice, and perish together. 
A. Brack Alca torda. £. A. rostro levi Brisson av. vi. 92. Tab. 8. 
LEED: compresso unisulcato, cor- (fig. 2. Hist. d’ois. ix. 396. 
pore toto subtus apicibusque Alca Pica. Gm. Lin. 551. 
remiguin posticarum albis. Alca unisulcata. Brunnich, 
(Junior avis.) Lath. Ind. 102. 
orn. 793. id. Syn. v. 320. Br. Zool. 137. Arct. Zool. it. 
Alca minor, le petit pingoin. 222. 
Descrip- Tu IS weighs only eighteen ounces: the length 
mes: Gs fifteen inches and a half ; the breadth twenty- 
five inches. The bill is of the same form with 
