OMN 
of Heaven ; it is still considered as emble • 
matic of peace and plenty ; the great quan- 
tity of oil which it produces in some coun- 
tries, effectually realizes the latter of these 
blessings. Unripe olives pickled, especially 
the Provence and Lucca sorts, are to many 
persons extremely grateful, they are sup- 
posed to promote digestion. 
OLERON laws, laws relating to mari- 
time affairs, and so called, becaxise made 
when King Richard I. was at the Isle of 
Oleron, in Aquitaine. 
OLFACTORY nei-ves, the first pair of 
the head; so called from their being the 
immediate instruments of smelling. 
OLIFIANT gas, a name given by the 
Dutch chemists to carburated hydrogen, or 
lieavy inflammable gas. See Gas. 
OLIGARCHY, a form of government 
wherein the administration of affairs is 
lodged in the hands of a few persons. See 
Government. 
OLIVE. See Oeea. 
OLIVINE, in mineralogy, a species of 
the Chrysolite family, found in the form of 
crystals, chiefly in basalt ; colour between 
asparagus and olive-green ; specific gravity 
3.y. It is infusible before the blow-pipe ; 
but witli borax it melts into a dark-green 
bead. Nitric acid dissolves its iron, and 
deprives it of colour. It is found very 
abundantly in many parts of Germany; 
also in France, Norway, and Sweden, and 
in our country : according to Klaprotli, it 
contains 
Silica 48 
Magnesia 37 
Lime 0.25 
Oxide of iron 12.5 
97.75 
Loss 2.25 
100 
QLYRA, in botany, a genus of the Mo- 
noecia Triandria class and order. Natural 
order of Gramina, Gramine®, or Grasses. 
Essential character : male, calyx glume one- 
flowered, awned ; corolla glume awnless. 
Female, calyx glume one-flowered, spread- 
ing, ovate; style bifid; seed cartilaginous. 
There are two species, viz. O. paniculata, 
and O. pauciflora, both natives of Jamaica. 
OMENTUM, the cawl, in anatomy, a 
membranaceous part, usually furnished 
with a large quantity of fat; being placed 
under the periton®um, and immediately 
above the intestines. See Anatomy. 
OMNIUM, a term in familiar use among 
ONI 
stock-brokers and speculators in the funds, 
to express the whole of the articles which 
the subscribers to a loan receive from 
government. Thus if the subscribers, ac- 
cording to their agreement with govern- 
ment are to have for every hundred pounds 
advanced a certain sum in 3 per cent, 
consols, a further sum in 4 per cents, and a 
proportion of the long annuities, the blank 
receipts which they receive for making the 
instalments on the several articles, are, 
when disposed of independent of each 
other, as the 3 per cent, consols only, call- 
ed scrip, but when the receipts are sold 
together as originally received, they are 
usually called omnium. As the omnium 
of every loan is the subject of extensive 
speculations, it generally is liable to con- 
siderable variations with respect to its cur- 
rent price, sometimes selling at a high pre- 
mium, at other times at a discount, ac- 
cording to the circumstances which take 
place between the agreement for tlie loan 
and the day fixed for paying the last instal- 
ment, Thus the omnium of the year 1799, 
was at first at 4 and 5 per cent, premium ; 
on the 28th of August it had risen to 19^, 
and on the 3d September was at 23^ ; it 
soon after fell considerably, and on the 
14th October was at 4|, 2^, 3| ; but on the 
18th November it had got up again to 12 
per cent, premium. The omnium of the 
year 1801 rose on the signing of preli- 
minaries of peace, to 18 per cent,, and 
was soon after at 25 per cent, premium : 
the omnium of the following year was at 
one time at 12 per cent, discount. 
OMPHALEA, in botany, a genus of the 
Monoecia Monadelphia class and order. 
Natural order of Tricocc®. EnphorbiEe, 
Jussieu. Essential character ; male, calyx 
four-leaved ; corolla none ; filaments colum- 
nar, with the anthers inserted into it : fe- 
male, calyx five-leaved ; corolla none ; 
stigma trifid ; capsule fleshy, three-celled ; 
nuts solitary. There are four species, all 
natives of Jamaica. 
ONCHIDIUM, in natural history, a 
genus of the Vermes Mollusca class and 
order. Body oblong, creeping, flat be- 
neath, mouth placed before; two feelers, 
situate above the mouth ; two arms at the 
side of the head ; vent behind and placed 
beneath. There is but a single species, viz, 
O. typh®, the onch, which is described in 
the Transactions of the Linn®an society. 
It inhabits Bengal, on the leaves of the 
typha elephantina about an inch long, and 
not quite so broad, but linear, and longer 
