BAL 
orustaceous and testaceous marine animals. 
It is said fo be a poisonous fish. B. vetula, 
or ancient file-fish, is likewise denominated 
the old wife fish, a name which it is supposed 
to have obtained from the appearance of the 
mouth when viewed in front, as well as from 
the slightly murmuring noise which it utters 
when first taken. B. maculatus, spotted 
file-fish ; is of an oval shape ; its length is 
about eighteen or twenty inehes, sometimes 
as much as two feet; colour pale violet; 
skin strongly marked into lozenge-sliaped 
reticulations; first dorsal fin three-rayed: 
the first very strong ; ventral spines rough, 
and but slightly projecting ; tail somewhat 
convex in the middle of the outline, with 
falcated tops ; whole body, dorsal and anal 
fin marked with numerous round blue spots. 
Native of the Indian and American seas. 
B. undulatus, or black file-fish, is a native of 
the Indian seas, observed first about the 
shores of Sumatra by the enterprizing and 
highly meritorious traveller Mungo Park. 
From the mouth to the base of the pectoral 
fins run three red lines, and the body is 
obliquely undulated by twelve lines of the 
same colour. See Plate II. Pisces, fig. 1. 
BALL, in the military art, comprehends 
all sorts of bullets for fire arms, from the 
cannon to the pistol. 
Cannon-balls are made of iron ; musket- 
balls, pistol-balls, &c. are of lead. The ex- 
periment has been tried of iron balls for 
pistols and fusees, but they are justly reject- 
ed, not only on account of their lightness, 
which prevents them from flying straight, 
but because they are apt to furrow the bar- 
rel of the pistol, &c. 
Cannon-balls are always distinguished by 
their respective calibres : thus, 
f 42' 1 
f 6.68 
32 
6.10 
24 
5.54 
18 
5.04 
, 12 
_ pound ball the 
4.40 
9 
diameter is " 
4.00 
6 
3.49 
3 
2.77 
2 
2.42 
l 1J 
11.92 
Ball and socket is an instrument made 
of brass, with a perpetual screw, so as to 
move horizontally, vertically, and obliquely; 
and is generally used for the managing of 
surveying insruments, and astronomical in- 
struments. 
BALLAD, in music, formerly a little 
history told in verse, and sung to the harp 
<ar viol, either by the author himself, or the 
BAL 
jongleur, whose profession it was to follow 
the bard and sing his works. About a 
century since the word ballad began to im- 
ply a brief, simple tale, conveyed in three 
or four verses, set to a short and familiar 
air, in which sense it is now understood. 
BALLAN CE, or Balance, in mechanics, 
one of the simple powers which serves to 
find out the equality or difference of weight 
in heavy bodies. See Mechanics. 
Ballance of trade, a term applied to the 
money ballance to be paid by one nation 
trading and carrying on business with an- 
other. So far as the articles mutually ex- 
ported and imported pay for each other, 
there is no balance ; but on which ever side 
the exports fall short in their amount, that 
nation is said to have the ballance of trade 
against it. See Trade. 
Ballance, hydrostatical. See Hydro- 
statics, 
Ballance of a clock or watch. See 
Clock-work and Watch-work. 
Ballance, to, in sea-langhage, to con- 
tract a sail into a narrower compass, and 
the term is applied particularly to the mizen 
of a ship, and the main-sail of those vessels 
in which it is extended by a boom. The 
operation of ballancing the mizen is per- 
formed by lowering the yard a little, then 
rolling up a small portion of the sail at the 
upper comer, and lashing it about one- fifth 
down towards the mast. A boom-sail is 
ballanced by rolling up a portion of the 
clue, or lower aftermost corner, and fasten- 
ing it strongly to the boom. 
BALLAST, a quantity of stones, gravel, 
or sand, laid in a ship’s hold, to make her 
sink to a certain depth into the water, and 
sail upright, rendering her of a prodigious 
weight. The ballast is sometimes one quar- 
ter, one-third, or one-half, according to the 
difference of the bulk of the ship. Flat vessels 
require the most ballast. Ships are said to be 
in ballast, when they have no other loading. 
Masters of vessels are obliged to declare the 
quantity of ballast they bear, and to unload 
it at certain places. They are prohibited 
unloading their ballast in havens, roads, &c. 
the neglect of which prohibition has ruined 
many excellent ports. All ships and vessels 
taking in ballast on the river Thames are 
bound to pay the corporation of the Trinity- 
house for eveiy ton carried to any ship in 
the coal trade Is. and for every other British 
ship, Is. 3d. For every ton carried to any 
foreign ship, Is. 7d. The Trinity-house 
employ men, and regulate them, and their 
lighters are to be marked. The art of bal- 
