281 
B U S 
posed directly to the sun., collects all the 
rays falling on it into a very small space, 
called the focus, where wood, or any other 
combustible matter being put, will be set on 
lire. The convex burning-glasses transmit 
the rays of light, and in their passage refract 
or incline them towards the axis, having the 
property of lenses, and acting according to the 
laws of refraction. The concave burning- 
glasses, or rather mirrors, being usually made 
of metal, reflect the rays of light, and in that 
reflection incline them to a point in the axis, 
having the property of mirrors, and acting 
according to the laws of reflection. See 
Optics. 
BURNISHER, a round polished piece of 
steel, serving to smooth and give a lustre to 
metals. Of these there are different kinds, of 
dijferent figures, straight, crooked, &c. Half 
burnishers are used to solder silver, as well as 
to give a lustre. 
Book-binders burnish the edges of their 
books by rubbing them with a dog’s tooth. 
Gold and silver are burnished by rubbing them 
with a wolf’s tooth, or by the bloody stone, 
or by tripoli, a piece of white wood, emery, 
&c. Deer are said to burnish their heads by 
rubbing off a downy white skin from their 
horns against a tree. 
BURR-PUMP, or Bilge-pump, differs 
from the common pump in having a staff' 6, 
7, or 8 feet long, with a bar of wood to which 
the leather is nailed, and this serves instead 
of a box. Two men, standing over the 
pump, thrust down this staff, to the middle 
whereof is fastened a rope, for 6, 8, or 10 to 
hale by, thus pulling it up and down. 
BURTON, in the sea-language, a small 
tackle consisting of two single blocks : it 
may be made fast any where at pleasure, for 
hoisting small things in and out, and will 
purchase more than a single tackle with two 
blocks. 
BURSERA, in botany, a genus of the 
dioecia polygamia class and order. The her- 
maphrodite calyx is triphyllous ; the corolla 
tripetalous; the male capsule carrions, tri- 
valved, and monospermous. The male is, 
corolla five-petalled, stamina ten. There is 
but one species, viz. 
Bursera gummifera, or gum elemi, (see 
Plate Nat. Hist, fig 70.) It is frequent in 
w ods in most of the Bahama islands, and 
grows speedily to a great height and thick- 
ness. The bark is brown and very like the 
birch. The wood is soft and useless, except 
when pieces of the limbs are put into the 
ground as fences, when'it grows readily, and 
becomes a durable barrier. The leaves are 
pinnate : the middle rib 3 or 6 inches long, 
with the pi nine set opposite on footstalks half 
an inch long. It has yellow flowers, male 
and female on different trees. 'These are 
succeeded by purple-coloured berries bigger 
than large peas, hanging in clusters on a stalk 
of about 5 inches long, to which each berry 
is joined by a footstalk half an inch long. The 
seed is hard, white, and of a triangular figure, 
inclosed within a thin capsule, which divides 
in 3 parts and discharges the seed. The fruit 
when cut, discharges a clear balsam, esteem- 
ed a good vulnerary, particularly for horses. 
On wounding the bark, a thick milky liquor 
is obtained, which soon concretes into a resin 
no way different from the gum elemi of the 
shops. 
BUSHEL, a measure or capacity for drv 
Vol. I. 
B IJ T 
goods, ns grain, fruits, dry pulse, con- 
taining four pecks or eight gallons, or one- 
eighth of a quarter. A bushel, by 12 Henry 
VIII. c. 5, is to contain, eight gallons of 
wheat : the gallon eight pounds of troy- 
weight; the ounce twenty sterlings, and the 
sterling thirty-two grains, or corns of wheat, 
growing in the midst of the ear. 
This standard bushel is kept in the ex- 
chequer, and it is found to contain 2145.6 
solid inches, and the water with which it has 
been filled weighed 1131 ounces and fourteen 
pennyweights troy. By act of parliament 
made in 1 697, it is determined that every 
round bushel with a plain and even bottom, 
being 18-J inches in diameter, and 8 inches 
deep, should be esteemed a legal Winchester 
bushel according to the standard in his ma- 
jesty’s exchequer. A vessel thus made will 
contain 2150.42 cubic inches, of course the 
com gallon contains 268.8 cubic inches. Be- 
sides the standard or legal bushel, there are 
several local bushels of different dimensions 
in different places. 
BUSKIN, a kind of shoe, somewhat in the 
manner of a boot, and adapted to either foot, 
and worn by either sex. This part of dress, 
covering both the foot and mid-leg, was tied 
underneath the knee ; it was very rich and 
line, and principally used on the stage by 
actors in tragedy. It was of a quadrangular 
form, and the sole was so thick, as that by 
means of it, men of the ordinary stature 
might be raised to the pitch and elevation of 
the heroes they personated. The colour was 
generally purple on the stage: herein it was 
distinguished from the sock, worn in comedy, 
that being only a low common shoe. The 
buskin seems to have been worn not only by 
actors, but by girls, to raise their height : 
travellers and hunters also made use of it to 
defend themselves from the mire. 
BUSS, in maritime affairs, a small sea-ves- 
sel, used by us and the Dutch in the herring- 
fishery, commonly from 48 to 60 tons burden, 
and sometimes more. A buss has two small 
sheds or cabins, one at the prow, and tire 
other at the stern ; that at the prow serves 
for a kitchen. 
BUTC II Y.W-bird, in ornithology. See La- 
NIUS. 
BUTEA, in botany, in honour of the late 
marquis of Bute. Class and order diadelphia 
decandria; nat. ord. papilionaceae ; calyx sub- 
labiate; corolla standard very long, lanceo- 
late; legume compressed, membranaceous, 
with one seed at the summit. There are two 
species; one an evergreen tree, about 15 
feet high, from which, when cut, exudes a 
gummy blood-red juice, of a sweetish taste. 
The second differs but little from the preced- 
ing. They are both natives of the East 
Indies, on the coasts of Malabar and Coro- 
mandel. 
BUTNERIA, a genus of the pentandria 
monogynia class and order. 'The essential 
character is; cor. five-petalled, filaments at 
top, connate with the petals; caps, live-grain- 
ed, mu r: cate. There are three species, 
shrubs of America and the West Indies. 
BUTOMUS, the flowering rush, or water 
gladiole ; a genus of the hexagynia order, in 
the enneandria class of plants, ranking, in the 
natural method, under the 5th order, tripe- 
taloideae. There is no calyx, but it has six 
petals, and as many monospermous capsules. 
There is but one species, viz. 
B t? T 
Butotmrt umbellatus, of which there are 
two varieties, the one with awhile, the other 
with a rose-coloured, flower. 'I hough com- 
mon plants, they are very pretty, and are 
worth propagating in a garden where there 
is conveniency for an artificial bog, or where 
there are ponds of standing water, as is many 
times the case. Where these conveniences 
are wanting, they may be planted in cisterns, 
which should be kept filled with water, with 
about a foot thickness of earth in the bottom; 
and into this earth the roots should be plant- 
ed, or the seeds sown as soon as they arc 
ripe. 
BUTT, in commerce, a vessel or measure 
of wine containing two hogsheads, or 126 
gallons. 
Butt, or butt-ends, in the sea-language, 
are the fore-ends of all planks under water, 
as they rise, and are joined one end to an- 
other. Butt-ends in great ships are most 
carefully bolted ; for if any one of them 
should spring or give way, the leak would be 
very dangerous, and difficult to stop. 
BUTTER, a fat unctuous substance, pre- 
pared from milk by the process of churning. 
It was late before the Greeks appear i«> 
have had any notion of butter; their poets 
make no mention of it, and yet frequent- 
ly speak of milk and cheese. The Romans 
used butter no otherwise than as a medicine, 
never as a food. The antient Christians of 
Egypt burnt butter in their lamps instead 
of oil ; and in the Roman churches, it was 
antiently allowed, during Christmas time, to 
burn butter instead of oil, on account of the 
great consumption of it otherwise. 
BUTTOCK of a ship, is that part of her 
which is her breadth right astern, from the 
tack upwards ; and a ship is said to have a 
broad or a narrow buttock, according as she 
is' built broad or narrow at the transum. 
BUTTON, an article of dress, serving to 
fasten clothes tight about the body, made of 
metal, silk, mohair, &c, in various forms. 
Metal buttons are formed two different ways; 
the blanks, or bases of the button, are either 
pierced out of a large sheet of metal, or cast. 
In the latter case, the shanks are previously 
fixed in the sand, exactly in the centre of 
the impression formed by each pattern, so 
as to have their extremities immersed in the 
melted metal, by which means they ava 
firmly fixed in the’ button when cooled. The 
former process is generally used for yellow 
buttons, and the latter for those ot’ white 
metal. 
The metal used for gilt buttons is an alloy 
of copper and zinc, containing more copper 
than goes to the composition of brass. This 
metal is rolled into sheets, and the blanks 
pierced out ; these are then planished, if for 
plain buttons; but when ornamented buttons 
are wanted the die is now struck, unless great 
nicety is required, when they are wrought, 
by the hand. The shanks, made with great 
expedition by a curious engine, are then at- 
tached to the bottom of each button by a 
wire clamp, like a pair of sugar-tongs, and a 
small quantity of solder and resin applied to 
each. They are then exposed to heat on an 
iron plate, containing about a gross, till the 
solder runs, and the shank becomes fixed io 
the button, after which they are singly put 
into a lathe, and their- edges turned off' 
smoothly. 'The surface of (he metal, which 
has become in a sural! degree oxidated Us 
