BLA 
buret of iron, it being compounded of 90 
parts of carbon, and 10 iron. See Iron, 
where its properties will be described. 
Black-lead is found in different countries, 
but the very best, and the fittest for mak- 
ing pencils is found at Borrowdale in Cum- 
berland, where it is obtained in such plenty, 
that not only the whole Island of Great 
Britain, but the Continent of Europe may 
be said to be supplied from thence. Be- 
side the application of this substance to the 
manufacture of pencils, it is made into 
retorts that will endure almost the strongest 
heat. The powder of black-lead is used in 
covering the straps for razors, and with it 
stoves, &c. are preserved from rust. 
Black rod, gentleman usher of, in British 
customs, is chief gentleman to the King. 
He has also the keeping of the chapter- 
house door, when a chapter of the Order 
of the Garter is sitting ; and in time of par- 
liament attends on the House of Peers. 
BLACKBURNIA, in botany, so called 
in honour of John Blackburne, Esq. and 
his daughter Anna, of Orford in Lanca- 
shire : a genus of the Tetrandria Monogynia 
class and order. Essential character : calyx 
four-toothed ; petals four, eliptic ; anthers 
heart-shaped ; germ conic ; stigma simple ; 
pericarp, berry, with a single seed. There is 
but one species, viz. bipinnata has the 
leaves alternate; abruptly pinnate, with 
two or three pairs of leaflets, which are 
opposite, quite entire, and very smooth ; 
panicles axillary, smaller. It is in habit 
not unlike ptelea trifoliata, and whether it 
ought to be separated from that genus can- 
not be determined, till we are better ac- 
quainted with the fruit. It is a native of 
Norfolk Island. 
BLACKWELLIA, in botany, a genus 
of the Dodecandria Pentagynia class and 
order. Calyx five-cleft, half superior ; corol 
fifteen-petalled ; capsules one celled, many- 
seeded. There are three species in the 
Asiatic islands. 
BLADHIA, in botany, so named from 
Peter John Bladh, a Swede, a genus of the 
Pentandria Monogynia class and order. 
Essential character : calyx wheel-shaped, 
deciduous; berry containing one arilled 
seed. There are three species, all natives of 
Japan. B. of which japonica has a perennial 
root, with small fibres, a shrubby stem, flex- 
uoses erect, very thinly branched, from 
four inches to a foot high. Flowers ax- 
ilary ; corolla white ; sweet smelling. 
BLADDER, a thin membranous sub- 
stance, found in several parts of an animal, 
BLA 
serving as a receptacle of some juice, or of 
some liquid excrement, as the urinary blad- 
der, gall bladder, &c. See Anatomy. 
BLADE, in commerce, a slender piece 
of metal, designed for cutting : thus we meet 
with sword-blade, blade of a chissel, blade 
of a saw, &c. 
BLiERIA, in botany, a genus of the 
Tetrandria Monogynia class of plants, the 
flower of which is monopetalous and cam- 
panulated : the tube is cyclindric, of the 
length of the cup, and pervious : the limb 
is small, and divided into four oval reflex 
segments : the fruit is an oblong quadran- 
gular capsule, with four cells, containing 
several roundish seeds. There are six spe- 
cies, all found at the Cape of Good Hope. 
BLAIR (John), an eminent chronolo- 
gist, was educated at Edinburgh. After- 
ward, coming to London, he was for some 
time usher of a school in Hedge-lane. In 
1754 he first published “The Chronology 
and History of the World, from the Crea- 
tion to the year of Christ 1753 ;” illustrated 
in 56 tables. In 1755 he was elected a 
Fellow of the Royal Society, and in 1761 
of the Society of Antiquaries. In 1756 he 
published a 2d edition of his “ Chronological 
Tables;” and in 1768 an improved edition 
of the same, with the addition of 14 maps 
of ancient and modern geography, for il- 
lustrating the Tables of Chronology and 
History ; to which is prefixed a “ Disserta- 
tion on the Progress of Geography.” In 
1757 he was appointed chaplain to the 
Princess Dowager of Wales, and mathema- 
tical tutor to the Duke of York : whom he 
attended in. 1763 in a tour to the continent 
from which they returned the year after. 
Dr. Blair had successively several good 
church livings: as a prebendal stall at 
Westminster, the vicarage of Hinckley, and 
the rectory of Burton Coggles in Lincoln- 
shire, all in 1761; the vicarage of St. 
Bride’s in London, in 1771, in exchange for 
that of Hinckley ; the rectory of St. John 
the Evangelist in Westminster, in 1776, in 
exchange for the vicarage of St. Bride’s; 
in the same year the rectory of Horton 
near Colebrooke, Bucks. Dr. Blair died 
the 24th of June, 1782. 
BLAKEA, in botany, so named from 
Martin Blake of Antigua, a genus of the 
Dodecandria Monogynia class and order. 
Essential character : calyx inferior, six- 
leaved ; superior, entire ; petals six ; cap- 
sules six-celled, many-seeded. There are but 
two species, of which B. trinervia generally 
grows to the height of ten or fourteen feet ; 
