LAB 
LAC 
\ 
and it is now become usual for chemists, 
among their other experiments on minerals, 
to mention their habitudes with the blow- 
pipe. 
Tiie fluxes which have obtaiued the ge- 
neral sanction of chemists, on account of 
the extensive use they have been applied to 
by Bergman, are phosphoric acid in the dry 
or glassy state, soda, and borax or the na- 
tive borate of soda. 
LABOUR, in general, denotes a close 
application to work or business. Among 
seamen a ship is said to be in labour when 
she rolls and tumbles very much, either a 
hull under sail, or at anchor. It is also 
spoke of a woman in travail, or child-birth. 
See Midwifery. 
LABRADOR stom, in mineralogy, is of 
a grey colour, passing into a dark ash. It 
exhibits, however, under certain circum- 
stances, a great variety of colours, as blue, 
green, yellow, red, and brown, in their dif- 
ferent shades. It shows, likewise, spotted 
and striped delineations. Sometimes the 
same spot if held in different directions 
changes its colour from blue to green, &c. 
The beautiful colours seldom extend over 
a whole piece ; in general, they show them- 
selves only in large and smaller spots and 
patches. Different colours are presented 
according as the piece is held between the 
light and the eye, or the eye and the light. 
It occurs massive, in blunt edged and rolled 
pieces. Its principal fracture is shining, 
passing into splendent. Specific gravity is 
about 2.7. It runs into a white enamel, with 
addition before the blow-pipe. The con- 
stitutent parts are 
Silica 69.5 
Alumina 13.6 
Sulphate of lime 12.0 
Oxide of copper o.7 
Oxide of iron 0.3 
96.1 
It makes a part of certain kinds of green 
stone, and is accompanied with mica and 
shorl, though seldom with iron pyrites. It 
was originally discovered by the Moravians, 
in the island of St. Paul, on the coast of 
Labrador, where it is still to be met with in 
plenty, also in some parts of Denmark and 
Norw’ay, and near the romantic Lake of 
Baikel in Siberia. It is used for many or- 
namental purposes. 
LABRUS, in natural history, a genus of 
fishes of the order Thoracici. Generic cha- 
racter : teeth strong and sharp ; the grin- 
ders sometimes' convex and crowded ; lips 
thick and doubled ; rays of the dorsal fin in 
several species prolonged into soft pro- 
cesses j gill-covers unarmed and scaly. 
There are ninety-eight species enumerated 
by Shaw, of which we shall notice merely 
the following : L. scarus, is about the length 
of twelve inches, and is found in the Medi- 
terranean in immense shoals. It was well 
known to tlie ancients, andhighly admired by 
them, being considered as one of the most 
luxurious dainties. For a representation of 
the blue-finned Labrus, see Plate V. fig. 2. 
LABYRINTH, in anatomy, the internal 
cavity of the ear, so called from sinuosities 
and windings. See Ear. 
Labyrinth, in gardening, a winding 
mazy walk between hedges, through a 
wood or wilderness. The chief aim is to 
make the walks so perplexed and intricate 
that a person may lose himself in them, 
and meet with as great a number of dis- 
appointments as possible. They are rarely 
to be met with except in great and nobis 
gardens, as Versailles, Hampton court, &c. 
There are two ways of making them ; the 
first is with single hedges ; this method has 
been practised in England : and these may, 
indeed, be best, where there is but, a small 
spot of ground allowed for making them ; 
but where there is ground enough the 
double is most eligible. Those made with 
double hedges, with a considerable thick- 
ness of wood between them, are approved 
as much better than single ones ; this is the 
manner of making them in France and 
other places; of all which that of Versailles 
is allowed to be the noblest of its kind in 
the world. It is an error to make them too 
narrow ; for that makes it necessary to 
keep the hedges close clipped : but ifj ac- 
cording to the foreign practice, they are 
made wide, tliey will not stand in need of 
it. The walks are made with gravel usually 
set with horn-beam : the pallisades ought to 
be ten, twelve, or fourteen feet high : the 
horn-beam should be kept cut, and the 
walks rolled. 
LAC, gum, in chemistry, is a very singu- 
lar compound, prepared by the female of a 
very minute insect, the coccus lacca, found 
on some trees in the East Indies, particular- 
ly the banyan fig. The insect is nourished 
by the tree, fixing itself upon the twigs and 
extremities of the succulent branches, where 
it deposits its eggs, which it glues to the 
branch by a red liquid, the outside of which 
hardens by the air, and serves as a cell for 
the parent insect. This increases in size. 
