D. Peirce.

Observer and record of agriculture, Science and art (Volume v.1) online

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ed with straw during winter, they
might by these means be guarded from
extreme cold, which would otherwise kill
them .




Letter G.

Galbanum, a gum issuing from the
stem of an umbelliferous plant, growing
in Persia, and many parts of Africa.

It is inflammable in the manner of a
resin, and soluble in water like a gum.

It attenuates arid dissolves tough
phlegm, and is therefore of service in
asthmas, and inveterate coughs, and in
many other complaints.

Galenic, or Galenical, in Pharmacy,
a manner of treating diseases. Galenical
medicines are those which are formed by
the easier preparation of herbs, roots, &c.,
by infusion, decoction, &c., and by com-
bining and multiplying ingredients; while
those oi chemistry draw their more inti-
mate and remote virtues by means of
fire, and elaborate preparations, as calci-
nation, digestion, fermentation, &c.

Gall, in natural history, denotes any
protuberance or tumor produced' by the
puncture of insects on plants and trees of
different kinds.

Galvanism, a term used to denote the
influence of metals by mere contact with
the animal body. It has been long as-
serted that when porter, (and some other
liquors also) is drunk out of a pewter pot,
it has a taste different from what it has
when drunk out of glass or earthen ware.

Gas, among chemists, a term used to
denote all the aerial and permanently elas-
tic fluids except atmospheric air.

Gastric Juice, among physicians, a
thin pelucid, spumous, and saltish liquor,
which continually distils from the glands
of the stomach, for the dilution of the

Gelatine, in chemistry, a jelly, pro-
duced from animal substances by frequent
washings in cold water; glue, size, and
isinglass, are all composed, in part, of
this substance.

Gelatine exists in great abundance in
animals; forming the constituent part of
their solid and fluid parts; its uses are
numerous. In a state of jelly, it consti-
tutes one of the most nourishing and pa-
latable species of food.

Gelatinous, in pharmacy and medi-
cine, any thing approaching to the gluti-
nous consistence of jelly.

Gem, in natural history, a common

name for all precious stones, of which
there are two classes, the pellucid and

The bodies composing the class of pel-
lucid gems, are bright, elegant, and beau-
tiful fossils, naturally and essentially com-
pound, ever found in detached masses,
extremely hard, and of great lustre.

The bodies composing the class of
semi-pellucid gems, are stones, naturally
and essentially compound, not inflammable,
nor soluble in water; found in detatched
masses, and composed of crystalline mat-
ter, debased by earths; however, they
are but slightly debased, and are of great
beauty and brightness, of a moderate de-
gree of transparency, and are usually
found in small masses.

The knowledge of gems depends prin-
cipally on observing their hardness and
color. For hardness, they are commonly
allowed to stand in the following order;
the diamond the hardest of all; then the
ruby, sapphire, hyacinth, emerald, ame-
thyst, garnet, carneol, chalcedony, onyx,
jasper, agate, porphyry, and marble. In
point of color the diamond is valued for
its transparency, the ruby for its purple,
the sapphire for its blue, the emerald for
its green, the hyacinth for its orange, the
amethyst for its violet, the carneol for its
carnation, the onyx for its tawny, the
jasper, agate, and porphyry for their ver-
million, green, and variegated colors, and
the garnet for its transparent blood-red.

Ge03Ietry, the science and doctrine
of local extension, as of lines, surfaces,
and solids, with that of ratios, &c.

The usefulness of this science extends
to almost every artand science. It is by
the help of it that engineers conduct all
their works. On geometry, likewise,
depends the theory of music, optics, per-
spective, drawing, mechanics, hydraulics,
pneumatics, &c.

Germination, in botany. When a
seed is placed, in a situation favorable to
vegetation, it very soon changes its ap-
pearance. The radicle is converted into
a root, and sinks into the earth; the
plumula, on the other hand, rises above
the earth, and becomes the trunk or stem.

When these changes take place, the
seed is said to germinate. The process
itself has been called germination, which



requires oxygen gas, and a certain de-
gree of heat and moisture to be present.
Seeds do not germinate well if they are
exposed to the action of light.

Oxymuriatic acid causes seeds to vege-
tate more rapidly when they are steeped
in it or watered with it; supposed to he
caused by the facility with which this
acid parts with its oxygen. This acid
seems even to augment the power of
seeds. Cases are stated where seeds had
been long kept, and refused to germinate,
grew rapidly when treated with this
acid. When a seed is jdaced in favorable
circumstances it gradually imbibes mois-
ture, and very soon after emits a quantity
of carbonic acid gas, even though no oxy-
gen gas should be present. If no oxy-
gen gas be present, the process stops here,
and no germination takes place. But if
oxygen gas be present, it is gradually ab-
sorbed by the seed; and at the same time
the farina of the cotyledons assume a
sweet taste. The quantity of oxygen
gas absorbed during germination, isalwaj'S
proportional to the carbonic acid gas
emitted; that is, the carbonic acid emit-
ted contains in it precisely the same
quantity of oxygen as has been absorbed.

Gilding is the application of gold to
the surfaces of bodies.

To write on paper with letters of
gold, put some gum arable into common
writing ink, and write with it in the
usual way. When the writing is dry,
» breathe on it; the warmth and moisture
soften the gum, and will cause it to fasten
on the gold-leaf, which may be laid on in
the usual way, and the superfluous part
brushed off. Or instead of this any
japanner's size may be used.

To make shell-gold. — Grind up gold-
leaf with honey in a mortar, then wash
away the honey with water, and mix the
gold powder with gum water. This may
be applied to any article with a camel's
hair pencil, in the same way as any other
color. — Glasses, &c. may be gilt by
drawing the figures with shell gold mix-
ed with gum arable and a little borax.
Then apply sufficient heat to it, and last-
ly burnish it. The work being thus gilt,
it is suffered to remain about twenty-four
hours, when the parts that are designed
to be burnished, are polished with a dog's

tooth, or, what is better, with an agate;
burnisher. The gilding must not be
quite dry when burnished; there is a
state proper for the purpose, which isi
only to be known by experience.

Gluten, a substance found in wheat
and various other vegetables, and con-
stituting an essential ingredient in the
formation of bread. It seems also to con-
stitute the essential part of yeast. It is
exceedingly, tenacious, ductile, and elas-
tic, hence the superior lightness of wheat
bread to that made from other grain: the
carbonic acid gas produced by fermenta
tion is retained by the gluten. Theforceol
this gas acting on the gluten causes it to
swell and form what is usually called
light bread; wheat contains a larger por-
tion of gluten than any other grain. Il
is also used for varnish, and a ground foi
paint, and is said in many cases to con-
stitute the base of the substance called
bird lime.

Gneiss, in mineralogy, is compose

Online LibraryD. PeirceObserver and record of agriculture, Science and art (Volume v.1) → online text (page 26 of 35)