E I T 
B I T 
B 1 X 
223 
year, and consist of 3G5 days : but because 
that was too much, every four-hundredth year 
was to remain b.ssextile. This method of 
computation is called the Gregorian, or new 
style ; it was received in most foreign coun- 
tries ever since the reforming of the calen- 
dar ; and by act of parliament passed in 
the twenty-fifth year of his late majesty’s 
i reign, viz. 1 75 1; it commenced in all the clo- 
I minions under the crown of Great Britain, 
in the year following ; ordering that the na- 
tural day following the second of September, 
[, should be accounted the fourteenth, omitting 
j the intermediate eleven days of the common 
I calendar. 
BISTT, in commerce, a small coin of 
t "Persia: some say that it is among the cur- 
| rent silver coins of Persia, and worth only a 
little above three farthings of our money; 
others speak of it again as a money of ac- 
i count. 
BISTORT. See Polyganum. 
BISTOURY, in surgery, an instrument 
for making incisions, of which there are dif- 
ferent kinds ; some being of the form of a 
lancet, others straight and fixed in the handle 
like a knife, and others crooked with the 
sharp edge on the inside. 
BISTRE, or Bister, among painters, de- 
I notes a glossy soot pulverised and made into 
a kind of cakes, with gum-water. It is used 
to wash their designs. 
Bistre is made by putting spot of dry wood, 
| as beech, into water, in the proportion of two 
' pounds to a gallon, and boiling them half an 
I hour. After the fluid has settled, pour off 
j the clearer part while it remains hot. Eva- 
' porate the fluid to dryness, and what remains 
I is good bistre. 
BIT, or Bitt, an essential part of a bridle, 
j There are many kinds of bits ; the most 
j simple is a short rod of iron, made rather 
wider than the mouth of the horse, and pro- 
vided with a hook or ring at each end for 
fastening the reins to. The next is a rod 
] similar to the former, broken in two pieces, 
and connected by a joint in the middle; 
i the former is intended for heavy draft 
t horses, the latter for those of light draft. 
The next is the snaffle, which is provided 
with two cross pieces that rest against the 
; lips or sides of the mouth; for as the snaffle 
j is intended for the saddle-horse, and the 
reins go to the hands, so the cross pieces 
are useful in preventing the bit from being 
drawn through the mouth. The number of 
| parts of which the mouth-piece of the snaffle 
j is composed, may be increased to any ex- 
; tent, as it may be made with 1 , 2, or several 
| joints; and hence it acquires new properties 
! and effects which require attention ; its 
gentleness or rigour will depend almost 
| wholly on these conditions. Another is the 
i curb bit, the mouth-piece of which is usually 
provided with an upset or arch in the middle, 
as, if perfectly straight, it would rest upon 
the tongue, and occasion an unpleasant re- 
I straint. It has been Sometimes called the 
liberty bit, on account of the freedom which 
it allows to the tongue ; by others it has 
been called the porte-mouth bit, vulgarly 
the Portsmouth-bit ; and by a supposed op- 
posite expression we gettheWeymouth-bit. 
Bit also denotes the iron part of a piercer, 
augre, and the like instruments. 
Bit of a key, the part which contains the 
wards. 
| Bits, or Bitts, in ship-building, the name 
| of two great timbers, usually placed abaft 
j the manger, in the ship’s loof, through which 
the cross-piece goes : the use of it is to belay 
the cable thereto, while the ship is at an- 
chor. 
BITTACLE, on ship-board, a square box 
standing before him that steers the ship, 
with the compass placed in it, to keep and 
direct the ship in her course. 
BITTER, a sea-term, signifying any turn 
of the cable about the bits, so as that the 
cable may be let out by little and little ; 
and when a ship is stopped by a cable, she is 
said to be brought up by a bitter. Also that 
end of the cable which is wound about the 
bits is called the bitter end of the cable. 
BITTERN, in the salt-works, the brine 
remaining after the salt is concreted: this 
they ladle oft’, that the salt may be taken out 
of the pan, and afterwards put in again ; when, 
being farther boiled, it yields more salt. See 
Salt. 
BITUMEN, in natural history, is under- 
stood by mineralogists in general, to be an 
oil which is found in different parts of the 
earth, in various states of consistence. These 
different states form distinct species ; in the 
arrangement of which we shall be guided by 
the observations which Mr. Hatchet has 
made in his valuable paper on bituminous 
substances. 
Sp. 1. Naphtha. This substance is found 
sometimes on the surface of the water of 
springs, and sometimes issuing from certain 
strata. It is found in great abundance in 
Persia. 
It is as fluid and transparent as water. 
Colour white, or yellowish white. Smell 
strong, but not disagreeable. Specific gra- 
vity when wiiite .708 or .729 ; when yellowish 
.8475. Feels greasy. Catches fire on the 
approach of flame, burns with a white flame, 
and leaves scarcely any residuum. 
Sp. 2. Petroleum. This substance is also 
found in Persia, and likewise in many coun- 
tries in Europe, particularly Italy, France, 
Switzerland, Germany, Sweden, England, 
and Scotland. It is not so fluid or transpa- 
rent as water. Colour yellow, either pale or 
with a shade of red or green ; reddish brown, 
and reddish black. Smell that of naphtha, 
but less pleasant. Specific gravity .8783. 
When burnt it yields a soot, and leaves a 
small quantity of coaly residuum. By expo- 
sure to the air it becomes like tar, and is then 
called mineral tar. 
Sp. 3. Mineral tar. This substance is 
found in many parts of Asia, America, and 
Europe. It is viscid, and of a black, brown- 
ish black, or reddish colour Smell some- 
times strong, but often faint. Specific gravity 
1.1. When burned, emits a disagreeable, 
bituminous smell. By exposure to the air it 
passes into mineral pitch and maltha. 
Sp. 4. Mineral pitch and maltha. This 
substance has a strong resemblance to com- 
mon pitch. When the weather is warm it is 
soft, and has some tenacity ; it is then called 
adhesive mineral pitch : when the weather is 
cold it is brittle : its hardness is 5 ; and its 
fracture has a glassy lusture. In this state it 
is called maltha. Colour black, dark brown, 
or reddish. Opaque. Specific gravity from 
1.45 to 2.07. Does not stain the lingers. 
On a white hot iron it flames with a strong 
smell, and leaves a quantity of grey ashes. 
It is to the presence of the earths which com- 
pose these ashes that the great specific gra- 
vity of this bitumen is to be ascribed. By 
farther induration it passes into asphalt, 
Sp. 5. Asphalt. This substance is found 
abundantly in many parts of Europe, Asia*, 
and America, especially in the island of Tri- 
nidad. 
Colour black, or brownish black. Lustre 
greasy, 2. Opaque. Fracture conchoidal, of 
a glassy lustre. Hardness from 7 to 8. 
Very brittle. Specific gravity 1.07 to 1.165. 
Feels smooth, but not greasy. Does not 
stain the fingers. Has little or no smell un- 
less when rubbed or heated. When heated, 
melts, swells, and inflames ; and when pure 
burns without leaving any ashes. 
Sp. 6. Mineral caoutchouc. This sub- 
stance was found about the year 1786 in the 
lead-mine of Odin, near Castletown, Derby- 
shire. It was first mentioned by Mr. De 
Born. 
Colour yellowish or reddish brown, some- 
times blackish brown. In its appearance it 
lias a strong resemblance to caoutchouc or 
Indian rubber ; hence its name. Consistency 
various: sometimes so soft as to adhere to 
the fingers ; sometimes nearly as hard as as- 
phalt. When soft it is elastic ; when hard, 
brittle. Specific gravity 0.9053 to 1.0233. 
Insoluble in alcohol, ether, and oil of tur- 
pentine, but soluble in oil of olives. Not 
affected by nitric acid. When distilled it 
yields a bituminous oil insoluble in alcohol* 
the residuum is carbonaceous. 
There is a variety of this substance found 
in a rivulet near the mine of Odin, which, 
when fresh cut, exactly resembles fine cork 
in colour and texture ; but in a few days 
after being exposed to the air, becomes ot a 
pale reddish brown. This substance contains 
within it a nucleus of elastic bitumen. It 
seems to be the elastic bitumen altered in its 
texture by the water. 
BIVALVES, one of the three general 
classes ofsbelL-fish, comprehending all those, 
the shells of which are composed of two 
pieces, joined together by a hinge. The 
Linnaian genera of bivalve shells are my a 
soien, teliina, cardium, mactra, donax, venus, 
spondylus, chama, area, astrea, anomia, ray- 
tillus, and pinna. 
BIVENTER, in anatomy, a muscle of the 
lower jaw, that has its origin in the incisure 
under the mastoid process. See Ana. 
BIXA, the roucou or anotto tree, a genus 
of the monogynia order, and polyandria class 
of plants ; and in the natural method ranking 
under the 37th order, columnifersc. 'The 
corolla is ten-petaled ; the calyx quinquedent- 
ed ; the capsule hispid and bivalved. Of this 
genus there is but one species known, viz. 
Bixa orellana, a native of the warm parts 
of America. It rises with an upright stem to 
the height of eight or ten feet, sending out 
many branches at the top forming a regular 
bed, with heart-shaped leaves ending in a 
point, and having long footstalks. Tfie 
flowers are produced in loose panicles at the 
end of the branches : these are of a pale peach- 
colour, having large petals, and a great num- 
ber of bristly stamina of the same colour in 
the centre. After the flower is past, the ger- 
men becomes a heart-shaped, or rather a 
mitre-shaped vessel, covered on tile outside 
with bristles opening with two valves, and 
