(sulphuric acid, or vitriolic acid,) an acid composed
of oxygen and sulphur.

_Orleans_, (Elizabeth Charlotte de Baviere,) _Duchess of_, second wife
of Philippe, the brother of Louis XIV., was born at Heidelberg, May 26,
1652, and died at the palace of St. Cloud, in Paris, December 8, 1722.
She was author of several works; among which were, Memoirs, and
Anecdotes, of the Court of Louis XIV.

_Ottoman_, a kind of hassock, or thick mat, for kneeling upon; so
called, from being used by the Ottomans or Turks.

_Oxalic acid_, a vegetable acid, which exists in sorrel.

_Oxide_, a compound (which is not acid) of a substance with oxygen; for
example, oxide of iron, or rust of metals.

_Oxidize_, to combine oxygen with a body without producing acidity.

_Oxygen_, vital air, a simple and very important substance, which exists
in the atmosphere, and supports the breathing of animals and the burning
of combustibles. It was called oxygen, from two Greek words, signifying
to produce acid, from its power of giving acidity to many compounds in
which it predominates.

_Oxygenized_, combined with oxygen.

_Pancreas_, a gland within the abdomen, just below and behind the
stomach, and providing a fluid to assist digestion. In animals, it is
called the sweet-bread. _Pancreatic_, belonging to the pancreas.

_Parterre_, a level division of ground, a flower garden.

_Pearlash_, the common name for impure carbonate of potash, which, in a
purer form, is called _Sal aeratus_.

_Peristaltic_, worm-like.

_Philosophy_, see _Intellectual_, _Moral_, and _Natural_.

_Physician in Ordinary to the Queen_, the Physician who attends the
Queen in ordinary cases of illness.

_Pistil_, that part of a flower, generally in the centre, composed of
the germ, style, and stigma, which receives the pollen or fertilizing
dust of the stamens.

_Pitt, William_, a celebrated English statesman, son of the Earl of
Chatham. He was born, May 28, 1759, and at the age of twenty-three, was
made Chancellor of the Exchequer, and soon afterward, Prime Minister. He
died, January 23, 1806.

_Political Economy_, the science which treats of the general causes
affecting the production, distribution, and consumption, of articles of
exchangeable value, in reference to their effects upon national wealth
and welfare.

_Pollen_, the fertilizing dust of flowers, produced by the stamens, and
falling upon the pistils, in order to render a flower capable of
producing fru