BRA 
BRA 
sire, and almost every thing that can be in- 
teresting on these subjects to the botanist, 
the gardener, and the farmer. 
BRATHYS, in botany, a genus of the 
Polyandria Pentagynia class and order. Na- 
tural order, Rotaceae. Hyperica, Jussieu. 
Essential character ; calyx tive-leaved ; pe- 
tals five; nectary none; capsule one-cell- 
ed, many-seeded. There is but one spe- 
cies; viz. B. juniperina, a shrub between 
heath and juniper, very branching and up- 
right, the branches covered with leaves; 
leaves opposite, very much crowded, ace- 
rose, an inch long, acute, unarmed, ever- 
green; flowers terminating the branches, 
several together, sessile. It is found in 
New Granada. 
BRAUNSPATH, pearl-spar, in mine- 
ralogy, is milk-white, though passing, by dif- 
ferent shades, to the brownish red : it oc- 
curs generally crystallized, and the forms 
of its crystals are the same as certain varie- 
ties of calcareous spar. Its primitive figure 
is a rhomboid, exactly corresponding with 
that of calcareous spar. It is found of other 
figures, which are described particularly by 
Hauy. The external lustre is more or less 
shining with a pearly lustre ; but, when in the 
first state of decomposition, it has usually a 
variegated semi-metallic appearance : it is a 
little harder than calcareous spar : the spe- 
cific gravity, according to Brisson, is 2.83; 
but the Isabella yellow variety has been 
found to be only 2.4. Before the blow- 
pipe it crackles and falls to pieces, and be- 
comes of a brownish black colour, but does 
not melt ; with borax it runs into a frothy 
flag ; it effervesces with acids when pulve- 
rized. The massive variety, when calcined 
and mixed with sand, forms a strong and 
valuable cement, which sets qnickly, and 
is impenetrable to water. The constituent 
parts are 
Carbonate of lime 50 
Oxide of iron 20 
Oxide of manganese... 28 
100 
It occurs chiefly in veins, accompanied 
by calcareous spar, galenablende, pyrites, 
and various ores of silver. It is found in 
the mines of Norway, Germany, Sweden, 
France, and in some parts of England and 
Wales. 
BRAWN, the flesh of a boar soneed or 
pickled ; for which end the boar should be 
old ; because the older he is, the more 
horny will the brawn be. 
BRAZIL wood, in the arts. The tree 
which bears this wood is the caesalpina cris- 
ta. Tire wood is very hard, takes a high 
polish, and is so heavy as to sink in water. 
When chewed it gives a sweetish taste. It 
much resembles in appearance red saun- 
riers wood, but differs from it essentially in 
readily giving out its colour to"vvater, which 
saunders wood does not. 
Brazil wood is valuable for the beautiful 
orange and red colours, in various shades, 
which it furnishes to the dyer, but the co- 
lour is naturally very fugitive, though it 
may be to a certain degree fixed by various 
mordants. When raspings of brazil wood 
are boiled for some time in water, they 
give a fine red decoction. The residue ap- 
pears black, but alkalies will continue to 
extract a colour from it after the action of 
water is exhausted. Spirit of wine and am- 
monia also extract a colour with great faci- 
lity, which is somewhat deeper than the wa- 
tery decoction. A decoction of brazil 
wood is readily turned of a violet or purple 
blue by alkalies, and this change is pro- 
duced by so very minute a quantity as to 
furnish a chemical test of the presence of 
alkalies of very great utility. According 
to Bergmann, 10 grains of crystallized car- 
bonate of soda, which contains no more than 
about 2.15 grains of mere alkali, dissolved 
v in something more than 5.5 English pints of 
water, give a sensible purple tinge to paper 
reddened by brazil wood. There is, how- 
ever, some ambiguity in this test, as the 
same change is produced by a solution of 
lime or magnesia in carbonic acid and wa- 
ter, a very frequent occurrence in most na- 
tural waters. Evaporating the water for 
some time will distinguish whether the 
change on brazil wood is produced by aH 
alkali or a corbonated earth ; for, if by the 
former, the purple will , be more intense in 
the concentrated water, as it now holds a 
greater proportion ot alkali ; but it by a 
carbonated earth, the effect will be lost, as 
the boiling expels the loose carbonic acid, 
and precipitates the carbonated earth which 
it held in solution. The effects of the solu- 
tions of tin and alum on brazil wood are the 
most important to the dyer. Alum added 
to the watery decoction of the wood gives a 
copious fine red precipitate, inclining to 
crimson, and. subsiding slowly. The super- 
natant liquor also retains the original red 
colour of the decoction, hut if enough of 
alkali is added to decompose the alum, its 
earth falls down and carries with it nearly 
all the remaining colouring matter of the 
