B O 1/ 
B O M 
BOM 
24<y 
2. Boletus igniarkis, or touchwood spunk, 
is frequent on the trunks of old trees ot 
al. kinds, especially a-h. It consists of a very 
hard woody substance, in shape like a horse’s 
hoof; and grows of various sizes, from a man’s 
list to that of his head and larger. The upper 
side is smooth, but uneven, distinguished near 
the rim by eivated zones of different colours, 
brown, grev, tawny, &c. 'J’he llesh is ol a 
tawny brown colour, extremely hard and 
tough. This fungus is made use ot in Germany 
and some parts of England for tinder. The 
G ermaus boil it in strong lev, dry it, and boil it 
again in solution of saltpetre. 1 he Laplanders 
burn if about their habitations, in order to 
keep, off a species of the gadfly, which is fatai 
to the young rein-deer. It has been used to 
stop the bleeding of the vessels utter ampu- 
tations. (Phil. Trans, vol. xlviii. p. 2.) For 
this purpose the hard outer part is cut oft, 
and the soft inner substance is beaten with a 
hammer to make it still softer. It is best when 
gathered in August or September. 
3. Boletus pini laricis, or agaric of the shops, 
grows on old latch trees. This fungus is an 
irregular spongy substance, extremely hght, 
eel of an uniform snowy whiteness; except 
the cortical part, which is usually taken off be- 
fore the aga.fr is brought into the shops. 
4. Boletus suberosus, or white cork spunk, 
grows commonly bn the trunks of birch 
and willow trees'. It grows sessile and hori- 
zontal ; its iigure is semicircular ; the upper 
side convex, the under nearly plain ; of va- 
rious dzos, t orn that of an ass’s hoof to a peck 
measure. The upper surface is ijuite white, 
generally covered with u short strong down, 
but sometimes smooth. The internal sub- 
stance is thick, white, tough, light, and 
spongy, like cork ; and is sometimes cut 
and shaped by the country people in Scotland 
for corks. 
BOLLITO, a name by which the Italians 
call a sea-green colour in artificial crystal. 
To prepare this colour, you must have in the 
f urnace a pot filled with forty p'ounds of good 
crystal, first carefully skimmed, boiled, and 
purified, without any manganese-: then you 
must have twelve ounces of the powder of 
small leaves of copper, thrice calcined, half 
an ounce of zaffer in powder ; mix them to- 
gether, and put them at four times into the 
pot, that they may the better mix with the 
glass ; stirring them well each time of pulling 
in the powder, for fear that it should swell 
too much and run over. 
HOLLOS, in the mines of Peru, a deno- 
mination given to the ingots or bars of silver 
procured therefrom the ore, bv the operation 
of lire, and the use of aquafortis. 
BOLONIAN stone, is a kind of mineral 
found near Bologna ; which, when duly pre- 
pared by calcination, makes a species of 
phosphorus. The property of this stone is, 
that though it has no lucid appearance in the 
dark, until it undergoes a particular calcina- 
tion, it becomes capable by previous prepa- 
ration, of imbibing, when exposed for a few 
minutes to the light of day, or even the flame 
of a candle, such a quantity of light, that it 
afterwards shines in the dark for several mi- 
nutes, like a glowing coal, but without any 
sensible heat. 
BOLSTERS, in sea language, small cu- 
shions, or bags, tilled with tarred canvas or 
rope-yarn, &c. and placed under the shrouds 
and stays, to prevent their chafing against 
the trestle-trees, by the motion of the mast, 
when the ship rocks at sea. 
’BOLT, among builders, an iron fastening 
fixed to doors and windows. They are ge- 
nerally distinguished into three kinds, viz. 
plate, round, and spring bolts. 
Bolts, in gunnery, arc of several sorts. 
See Gunnery. 
Bolts, in a ship, are iron pins, of which 
there are several sorts, according to their 
different make and uses. Such are drive 
bolts, used to drive out others: ray bolts, 
with jags or barbs on each side, to keep them 
from living out of their holes: clench bolts, 
which are clenched with rivetting hammers : 
forelock bolts, w hich have at the end a fore- 
lock of iron driven in to keep them from 
starting back: set bolts, used tor forcing the 
planks, and bringing them close together : 
tend, or fender bolts, made with long and 
thick heads, and struck into the uttermost 
bends of the ship, to save her sides from 
bruises: and ring bolts, used for brinking to 
the planks, and those parts whereto arc fast- 
ened the breeches and tackles of the guns. 
Bolt of canvas, in commerce, the quan- 
tity of 28 ells. 
BOMB, in military affairs, a globe or shell 
of cast iron, having a vent to receive the fuse, 
which is made of wood. The shell being 
filled with gunpowder, the fuse is driven 
into the vent or aperture, within an inch of 
the head, and fastened vvitJi a cement made 
of quick-lime, ashes, brick-dust, and steel- 
filings, worked together in a glutinous wa- 
tt. r ; or of four parts of pitch, two of colopho- 
ny, one of turpentine, and one of wax. This 
tube is filled with a combustible matter, made 
of two ounces of nitre, one of sulphur, and 
three of gunpowder-dust, well rammed. To 
preserve the fuse, they pitch it over, but 
uncase it when they put the bomb into the 
mortar, and cover it with gunpowder-dust ; 
which having taken fire by the Hash of the 
powder in the chamber of the mortar, burns 
all the time the bomb is in the air ; and the 
composition in the fuse being spent, it fires 
the powder in the bomb, which bursts with 
great force, blowing up whatever is about it. 
The.great height the bomb goes in the air, 
and the force with which it falls, make it go 
deep into the earth. 
Bomb-c/ics*, a kind of chest filled usually 
with bombs, sometimes only with gunpowder, 
placed under ground to tear it and blow it 
up into the air, with those who stand on it. 
It was set on fire by means of a saucisse fast- 
ened at one end, but is now much disused. 
BOMBARDMENT, the act of assaulting 
a city or fortress, by throwing shells into it, 
in order to set fire to and ruin the houses, 
churches, magazines, &c. and to do other mis- 
chief. As one of the effects of the shell re- 
sults from its weight, it is never discharged as 
a ball from a cannon, that is, by pointing it 
point blank at a certain object; but the mor- 
tars in England are fixed at an elevation of 
45 degrees ; that is, inclined so many degrees 
from the horizon, that the shell describes a 
curve, called the military projectile. Hence 
a mortar, whose trunnions are placed at the 
breech, can have no point-blank range. Mor- 
tars should be so contrived, that they may 
be elevated to any degree required, as much 
preferable to those fixed at an angle of 4.B ; 
because shells should never be thrown at 
that angle but in one single case only, which 
seldom happens ; that is, when the battery 
is so far off, that they cannot otherwise reach 
the works: for when shells are thrown from 
the trenches into the works of a fortification, 
or from the town into the trenches, they 
should have as little elevation as possible, in 
order to roll along, and not bury themselves ; 
whereby the damage they do, and the ’.error 
they cause to the troops, is much greater 
than if they sink into the ground. . On t he 
contrary, when shells are thrown upon ma- 
gazines, or any other buildings, with an in- 
tention to destroy them, the mortar should j 
be elevated as high as possible, that the shells \ 
may acquire a greater force in their fall. 
Shells should be loaded with no more ; 
powder than is requisite to burst them into I 
the greatest number of pieces, and the length I 
of the fuses should be exactly calculated ac- ! 
cording to the required ranges; for, should 
the fuse set fire to the powder in the shell be- j 
fore it falls on the place intended, the shell ; 
will burst in the air, and probably do more j 
mischief to those who fired the mortar than 
to those against whom it was discharged. To j 
prevent this, the fuses are divided into as ! 
many seconds as the greatest range requires, j 
consequently may be cut to any distance, at 
an elevation of 45 degrees. 
Mortars are not to be tired with two fires ; 
for when the fuse is properly fixed, and both j 
fuse and shell dredged with mealed powder, j 
the blast of the powder in the chamber of the, 
mortar, when inflamed by the tube, will like- 
wise set lire to the fuse in the shell. 
BOMBASINE, a name given to two sorts 
of stuff's, the one of siik, and the other cross- , 
ed of cotton. 
Bombasine of silk pays duty on importation 
as other foreign silks. See Silk. That of 
cotton pays each piece, a duty according 
to its width. 
BOMBAX, in botany, the silk cotton-tree : ] 
a genus of the polyandria order, and mono-] 
delphia class of plants; and in the natural 
method rankingunder the 37th order, colum- 
niferae. The calyx is quinquiiid ; the stamina 
are five or more ; the capsule is ligneous, 
quinquelocular, and quinquevalved; the seeds 
are woolly, and the receptacle peutagonous. 
The species are: 
1. Bombax ceiba, with a prickly stalk. 
2. Bombax heptaphyllum, with leaves cut 
into seven parts. The cotton is of a fine 
purple colour, but the size of the tree is not 
partieularlv mentioned by botanical writers, i 
3. Bombax pentandrum, with a smooth 
stalk. This and the ceiba grow naturally in 
both the Indies, wlffere they arrive at a great 
magnitude, being some of the largest trees in 
these parts. Bosnian says, he has seen in, 
Guinea trees of this kind so w idely diffused,, 
that 20,000 armed men might stand under the 
branches of one. They generally grow with 
straight stems. Those of the ceiba are armed 
with short strong spines; but the pentandrum 
has a very smooth stem, which in the young, 
plant is of a bright green; but after a few 
years is covered with a grey or ash-coloured 
bark, which turns brown as they grow older. 
The branches towards the top are furnished 
with leayes composed of five, seven, or nine, 
oblong smooth little leaves, spear-shaped, 
and joined to one common centre at their 
base, where they adhere to the long foot- 
stalk. The flower buds appear at the end of 
the branches ; and soon alter the flowers ex- 
