SEC 
sebacic, the properties of which are quite 
distinct from those which had been for- 
merly described. The process by which 
Thenard obtained the sebacic acid is the 
following. He distilled a quantity of hogs- 
lard, and washed the product several times 
with hot water. He then dropped into it 
acetate of lead ; there was formed a flakey 
precipitate, which was collected and dried, 
put into a retort with sulphuric acid, and 
heated. The liquor in the receiver had no 
acid character ; but there appeared in the 
retort a melted matter analogous to fat. 
This is carefully separated ; and after being 
washed, is boiled with w'ater. By the 
action of heat the whole is dissolved by the 
water, and when it cools, crystals in the 
shape of needles are deposited. These are 
the sebacic acid which has the following 
properties. It has no smell, a slight acid 
taste, and reddens strongly the tincture of 
turnsole. When heated it melts like tallow. 
It is much more soluble in warm than in 
cold water. Alcohol dissolves it in large 
quantities. Boiling water saturated with 
this acid forms a solid mass on cooling. It 
crystallizes in small needles, but with certain 
precautions may be obtained in the form of 
long, large, and very brilliant plates. It pre- 
cipitates the acetate and nitrate of mercury 
and lead, and nitrate of silver ; it neutralizes 
tlie alkalies, and forms with them soluble 
salts. 
SEBATES, in chemistry, salts formed of 
the sebacic acids, and alkalies, earths, &c. ; 
they are soluble in water. 
SECALE, in botany, rye, a genus of the 
Triandria Digynia class and order. Natu- 
ral order of Gramina or Grasses. Essential 
character ; calyx opposite, two-valved, 
two-flowergd, solitary. There are four 
species, viz. the villosum, orientale, creti- 
cum, and cercale. S. villosum, or wood rye- 
grass, is distinguished by a calyx with 
wedge-shaped scales, and by the fringe of 
the glume being woolly. The glumes of the 
S, orientale are shaggy, and the scales of the 
calyx are shaped like an awl. The glumes 
of the S. cretichm are fringed on the outside. 
The S. cereale, or common rye, has glumes 
with rough fringes. It is a native of the 
island of Candia, was introduced into Eng- 
land many ages ago, and is the only species 
of rye cultivated in this kingdom, There 
are, however, two varieties, the winter and 
spring rye. The winter rye, which is 
larger in the grain than the spring rye, is 
sown in autumn at the same time with 
wheat, and sometimes mixed with it j but 
SEC 
as the rye ripens sooner than the wheat, 
this method must be very exceptionable. 
The spring rye is sown along with oats, and 
usually ripens as soon as the winter rye ; 
but the grain produced is lighter, and it is 
therefore seldom sown except where the 
autumnal crop has failed. Rye is com- 
monly sown on poor, dry, limestone, or 
sandy soils, where wheat will not thrive. By 
continuing to sow it on such a soil for two 
or three years, it will at length ripen a 
month earlier than that which has been 
raised for years on strong cold ground. 
■SECANT, in geometry, is a line that 
cuts another, or divides it into two parts. 
In trigonometry, the secant denotes a 
right line drawn from the centre of a circle, 
which cutting the circumference, proceeds 
till it meets with a tangent to the same circle. 
SECHIUM, in botany, a genus of the 
Monoecia Syngenesia class and order. Na- 
tural order ofEuphorbiae, Jussieu, Essential 
character : calyx half, five-cleft ; corolla 
five-cleft, with ten hollows in the upper 
part of the tube ; nectary : male, filaments 
five, connected : female, stigma very large, 
peltate reflexed, five-cleft ; pericarpium 
large, ovate, turbinate, one-seeded. There 
is only one species, viz. S. edule, the chocho 
vine. It is a native of the West Indies ; 
flowering and fruiting in December. 
SECOND, in geometry, chronology, &c. 
the sixtieth part of a prime or minute; 
whether of a degree, or of an hour ; it is 
denoted by two small accents, thus ("). 
SECRETARY, an officer who by his 
master’s orders writes letters, dispatches, 
and other instruments, which he renders 
authentic by his signet. Of these there are 
several kinds; as, 1. Secretaries of State, 
who are officers that have under their ma- 
nagement and direction the most important 
affairs of the kingdom, and are obliged 
constantly to attend on the King: they re- 
ceive and dispatch whatever comes to their 
hands, either from the crown, the church, 
the army, private grants, pardons, dispen. 
sations, &c. as likewise petitions to the so- 
vereign, which, when read, are returned to 
them ; all which they dispatch according to 
the King’s direction. They have authority to 
commit persons for treason and other of- 
fences against the state, as conservators of 
the peace, at common law, or as justices 
of the peace throughout the kingdom. They 
are members of the Privy Council, w’hich 
is seldom or never held without one of them 
being present ; and as to the business and 
correspondence in all parts of this kingdom, 
