BOA 
B O C 
BOG 
inets, so that the rower can pi ill either way. 
I he boat is steered with an oar at each encl ; 
and the steering oar is one-third longer than 
the rowing oar. The platform placed at the 
bottom, within the boat, is horizontal, the 
length of the midships, and elevated at the 
ends for the convenience of the steersman, 
to giye him a greater power with the oar. 
The internal part of the boat next the sides, 
from the under part of the thwarts down to 
the platform, is cased with cork ; the whole 
quantity of which, affixed to the life-boat, is 
nearly seven hundredweight, j The cork in- 
disputably contributes much to the buoyancy 
of the boat, is a good defence in going along- 
side, a vessel, and is of principal use in keep- 
ing the boat in an erect position in the sea, 
or rather for giving her a very lively and 
quick disposition to recover from any sudden 
cunt or Lurch which she may receive from 
the stroke ot a heavy wave. But, exclusively 
ot the cork, the admirable construction of 
this boat gives it a decided pre-eminence. 
The ends being similar, the boat can be row- 
ed either way; and this peculiarity of form 
assists her in rising over the waves. The 
curvature of the keel and bottom facilitates 
her movement in turning, and contributes to 
the ease of the steerage, as a single stroke of 
the steering oar has an immediate effect, the 
boat moving as upon a centre. The tine 
entrance below is of use in dividing the 
waves, when rowing against them ; and, 
combined with the convexity of the bottom, 
and the elliptical form of the stem, admits 
her to rise with wonderful buoyancy in a high 
sea, and to launch forward" with rapidity, 
without shipping any water, when a common 
boat would be in danger of being tilled. The 
flannelling or spreading form of the boat, 
from her Hoor-heads to the gunwale, gives 
her a considerable bearing; and the continu- 
ation of the breadth, well forward, is a great 
support to her in the sea ; and it lias been 
found by experience that boats of this con- 
struction are the best sea boats for rowing 
against turbulent waves. The internal shal- 
lowness ot the boat from the gunwale down 
to the platform, the convexity of the form, 
and the bulk ot cork within, leave a very di- 
minished space for the water to occupy': so 
th.it the lite-boat, when Idled with water, con- 
tains a considerable less quantity than the 
common boat, and is in no danger either of 
sinking or overturning. It may lie presumed 
by some, that in cases ot high wind, agitated 
sea, and broken waves, a boat of such' a bulk 
could not prevail against them by the force 
of oars ; but the life-boat, from her peculiar 
form, may be rowed a-head, when the at- 
tempt in other boats would fail. Boats of 
the common form, adapted for speed, are of 
course put in motion with a small power; 
but, for want of buoyancy and bearing, are 
over-run by the waves, and sunk when im- 
pelled against them ; and boats constructed 
for burthen meet with too much resistance 
from the wind and sea when opposed to them, 
and cannot in such cases be rowed from the 
shore to a ship in distress. 
Mr. Greathead gives the following instruc- 
tions for the management of the life-boat : 
l'he boats, in general, of this description, 
are painted white on the outside ; this colour 
more immediately engaging the eye o 1 ' the j 
spectator when rising from the hollow of the 
sea than any other. The bottom of the boat 
is at iirst varnished (which will take paint af- 
terwards), for the more minute inspection of 
purchasers. The oars she is equipped with 
are made of fir of the best quality ; having 
found by experience that a rove ash oar, 
that will dress clean and light, is too pliant 
among the breakers ; and when made strong 
and heavy, from row ing double-banked, the 
purchase being short, sooner exhausts the 
row er ; which renders the lir o.ar, when made 
stiffi preferable. 
In the management of the boat she requires 
twelve men to work her: that is, five men 
on each side rowing double-banked, with an 
oar slung over an iron thole, with a grommet 
(as provided), so as to enable llte rower to 
pull either w ay, and one man at each end to 
steer her, and to be ready at the opposite 
end to take the steer-oar when wanted. As, 
from the construction of the boat, she is al- 
ways in a position to be rowed either way, 
without turning the boat: when manned, the 
person who steers her should be well ac- 
quainted with the course of the tides, in or- 
der to take every possible advantage: the 
best method, if the direction will admit of it, 
is to head the sea. The steersman should 
keep his eye fixed upon the wave or breaker, 
and encourage the rowers to give way as the 
boat rises to it ; being then aided by the force 
of the oars, she launches over it with vast 
rapidity, without shipping any water. It is 
necessary to observe, that there is often a 
strong reflux of sea occasioned by the strand- 
ed wrecks, which requires both dispatch and 
care in the people employed that the boat be 
not damaged. When the wreck is reached, 
it the wind blows to the land, the boat will 
come in shore without any other effort than 
steering. 
BOATSWAIN, a ship-officer, to whom is 
committed the charge of all the tacklings, 
sails and rigging; ropes, cables, anchors, Bags, 
pendants, &c. He is also to take care of the 
long-boat and its furniture, and to steer her ei- 
ther by himself or his mate. He calls out the 
several gangs and companies aboard, to the due 
execution of their watches, works, spells, &c. 
He is likewise provost-marshal, who sees and 
punishes all offenders sentenced by the cap- 
tain, or a court-martial of the fleet. 
BOB, or hall, is a metallic weight, attached 
to the lower extremity of a pendulum-rod, by 
means of a tapped adjusting nut, at such a 
distance from the point of suspension as the 
time of a given vibration requires. 
BOBBIN, a small piece of wood turned 
in the form of a cylinder, with a little border 
jutting out at each end, bored through to re- 
ceive a small iron pivot. It serves to spin 
with the spinning-wheel ; or to wind thread, 
worsted, hair, cotton, silk, gold, and silver. 
BOCAUDO, among logicians, the fifth 
mode of the third figure of syllogisms, in 
which the middle proposition is an universal 
affirmative, and the iirst and last particular 
negatives, thus : 
Bo Some sickly persons are not students ; 
car Every sickly person is pale: 
do Therefore some persons are pale that 
are not students. 
BOC’C ON I A, greater tree celandine : a ge- 
nus of the monogynia order, and dodecandria 
c lass of plants, and in the natural method rank- 
ing under the 27th order, rhoeadeae. The 
calyx is diphyllous ; there is no corolla ; the 
stylus is bifid : the berry is dry, and mono- 
spermous. Of this genus there is but one 
known species, viz. 
Bocconia Jruesctns, which is esteenred 
for the beauty of its large foliage. It is very 
common in Jamaica and the warm parts of 
America, where it grows to the height of 1 0 
or 12 feet, having a straight trunk as large as 
a man’s arm, and covered with a white smooth 
bark. At the top it divides into several 
branches, on which the leaves are placed al- 
ternately. These leaves are 8 or 9 indies 
long, and 5 or 6 broad ; and are of a fine 
glaucous colour, l’he whole plant abounds 
with a yellow juice of an acrid nature ; so 
that it is used by the inhabitants of America 
to take off warts and spots from the eyes, die 
singular beauty of this plant renders it wort! y 
of a place in every curious collection : and it 
seems the Indians are very fond of it ; for 
Hernandez tells us, their kings used to plant 
it in their gardens. It is propagated by seeds 
horn America, and must always be kept in a 
stove. 
BOCK-I.AN D, in the Saxons’ time, is what 
we now call freehold lands, held by the bet- 
ter sort of persons by charter or deed in writ- 
ing ; by which name it was distinguished from 
folkland, or copy-hold land, holden by the 
common people without writing. 
BODY, in physics, an extended solid sub- 
stance, of itself utterly passive and inactive, 
indifferent either to motion or rest ; but ca- 
pable of any sort of motion, and of all figures 
and forms. 
Descent o/’Bodies. Heavy bodies, in au 
unresisting medium, fall with an uniformly ac- 
celerated motion; whence the spaces de- 
scended are in the duplicate ratio of the 
times and velocity, and increase according to 
the uneven numbers 1, 3, 5, &c. The times 
and velocities are in a subduplicate ratio of 
the spaces. The velocity of descending bo- 
dies is in proportion to the times from the be- 
ginning of their tall ; and the spaces described 
by a falling body, are as the- squares of the 
times from the beginning of their fall. See 
Mechanics. 
Body, in geometry, the regular bodies, or 
those which have all their angles and sides si- 
milar and equal, are five, viz. tetrahedron, oc- 
tahedron, dodecahedron, icosahedron, and the 
cube. 
Body, among painters, as to bear a body, 
a term signifying that the colours are of such 
a nature as to be capable of being ground so 
line, and mixing with the oil so entirely, as to 
seem only a very thick oil of the same co- 
lour. 
BOEHMERIA, a genus of the moncec.ia 
tetrandria class and order. The essential cha- 
racter is, male, calyx four-parted ; corolla 
none. Female, calyx none ; germ obovate ; 
style single ; seed single, compressed. 
T here are 5 species, natives of America and 
the W est Indies. 
BOEEHAAYlA, a genus of the mono- 
gynia order, and monandria class of plants. 
There is no calyx; the corolla is monope- 
talous, campamilated, and plaited ; and the 
seed is one, naked, and below. There are 7 
species, all natives of the Indies. Some of 
these plants rise 5 or 6 feet high, but most of 
them only 18 inches or 2 feet. T hey bear 
flowers of a yellow or red colour. 
BOG prop erly signifies a quagmire, co- 
vered indeed with grass, but not solid enough 
