_____ 
AUR 
peror’s justice, and aulic council. The aulic 
court ceases at the death of the emperor, 
whereas the imperial chamber of Spire is 
perpetual, representing not only the deceas- 
ed emperor, but the whole Germanic body, 
which is reputed never to die. 
AVOIRDUPOIS, or Averdupois 
weight, a sort of weight used in England, 
the pound whereof is made up of sixteen 
ounces. 
This is the weight for the larger and 
coarser commodities, such as groceries, 
cheese, wool, lead, &c. Bakers who live 
not in corporation-towns, are to make their 
bread by avoirdupois weight, those in cor- 
porations, by troy weight. Apothecaries 
buy by avoirdupois weight, but sell by troy. 
The avoirdupois ounce is less than the troy 
ounce, in the proportion of 700 to 768 ; but 
the avoirdupois pound is greater than the 
troy pound in the proportion of 700 to 576, 
or as 17 to 14 nearly : for 
1 lb. avoirdupois = 7000 grains troy. 
1 lb. troy . = 5760 do. 
1 oz. avoirdupois = 4371 do. 
1 oz. troy = 480 do. 
AVOWEE, one who has a right to pre- 
sent to a benefice. See Ad vow son. , 
AURELIA, in natural history, a term 
formerly employed by naturalists to express 
that intermediate state in which all lepidop- 
terous, and most other insects, remain for 
some time, between the caterpillar form and 
the period in which they are furnished with 
wings, with antennae, and other organs ap- 
pertaining to the perfect insect. Aurelia 
and crysalis are synonymous words, both al- 
luding to the golden splendour of the case in 
which the creature, during that state, is 
contained. This brilliant appearance seems 
to be confined to the Papilio tribe, so that 
the terms aurelia and chrysalis are altoge- 
ther inapplicable, in a general manner, to 
insects in that state, These terms are now 
discarded in favour of the more expressive 
one pupa, which Linnaeus has adopted in 
their stead ; a term which implies that the 
insect, like an infant, remains in its swaddling 
clothes. 
AURICLE, in anatomy, that part of the 
ear which is prominent from the head, cal- 
led by many authors auris externa. 
Auricles of the heart. These are a kind 
of appendages of the heart at its base, and 
are distinguished by the names of the right 
and left. The right auricle is much larger 
than the left, and this is placed in the hinder, 
AUR 
that in the anterior part. They are intended 
as diverticula for the blood, during the sy- 
stole. Their substance is muscular, being 
composed of strong fibres, and their motion 
is not synchronous but achronous with that 
of the heart. See Anatomy. 
AURICULAR medicines, such as are 
used in the cure of distempers in the ear. 
AURIGA, the Waggoner, in astronomy, 
a constellation of the northern hemisphere, 
consisting of 23 stars, according to Tycho, 
40 according to Hevelius, and 66 in the 
Britannic Catalogue. This constellation is 
represented by the figure of an old man, in 
a posture somewhat like sitting, with a goat 
and her kids in his left hand, and a bridle in 
his right. 
AURORA borealis, or Aurora septen- 
trionalis, in physiology, the northern dawn 
or light, sometimes called streamers, is an 
extraordinary meteor, or luminous appear- 
ance, shewing itself in the night-time in the 
northern part of the heavens: and most 
usually in frosty weather. It is usually of 
a reddish colour, inclining to yellow, and 
sends out frequent corruscations of pale light, 
which seem to rise from the horizon in a 
pyramidal undulating form, and shoot with 
great velocity up to the zenith. The au- 
rora borealis appears frequently in form of 
an arch, chiefly in the spring and autumn, 
after a dry year. The arch is partly bright, 
partly dark, but generally transparent; 
and the matter of which it consists is also 
found to have no effect on the rays of light 
which pass through it. Dr. Hamilton ob- 
serves, that he could lainly discern the 
smallest speck in the Pleiades through the 
density of those clouds which formed the 
aurora borealis in 1763, without the least 
diminution of its splendour, or increase of 
twinkling. 
This kind of meteor, which is more un- 
common as we approach towards the equa- 
tor, is almost constant during the long win- 
ter, and appears with the greatest lustre in 
the polar regions. In the Shetland isles, 
the'“ merry dancers,” as the northern lights 
are there called, are the constant atten- 
dants of clear evenings, and afford great 
relief amidst the gloom of the long winter 
nights. They commonly appear at twilight, 
near the horizon, of a dun colour, approach- 
ing to yellow; they sometimes continue 
in that state for several hours, without any 
perceptible motion; and afterwards they 
break out into streams of stronger light, 
spreading into columns, and altering slowly 
into 10,000 different shapes, and varying 
