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Metallic oxides.


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Loss,




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Besides the principles, the nature of
which has been just discussed, others
have been described by chemists as be-
longing to the vegetable kingdom. Thus
a substance somewhat analogous to the
muscular fibre of animals has been de-



tected by Vauquelin in the papavv; and
a matter similar to animal gelatine by
Braconnot, in the mushroom; but in this
place it would be improper to dwell upon
peculiarities, my object being to offer
such general views oif the constitution of
vegetables, as may be of use to the agri-
culturist. Some distinctions have been
adopted by systematical authors, which I
have not entered into, because they do
not appear to me essential to this inquiry.
Dr. Thomson, in his elaborate and learn-
ed system of chemistry, has described six
vegetable substances, which he calls mu-
cus, jelly, sarcocol, asparagin, inulin, and
ulmin. He states that mucus exists in
its purest form in linseed; but Vauquelin
has lately shown that the mucilage of lin-
seed is, in its essential characters, analo-
gous to gum; but that it is combined with
a substance similar to animal mucus;
vegetable jelly, Dr. Thomson himself
considers as a modification of gum. It is
probable, from the taste of sarcocol, that
it is gum combined with a little sugar.
Inulin is so analogous to starch, that it is
probably a variety of that principle; ul-
min has been lately shown by Mr. Smith-
son to be a compound of a peculiar ex-
tractive matter and potassa; and asparagin
is probably a similar combination. If
slight differences in chemical and physi-
cal properties be considered as sufficient
to establish a difference in the species of
vegetable substances, the catalogue of
them might be enlarged to almost any
extent. No two compounds procured
from different vegetables are precisely
alike; and there are even differences in
the qualities of the same compound, ac-
cording to the time in which it has been
collected, and the manner in which it has
been prepared: the great use of classifi-
cation in science is to assist the memory;
and it ought to be founded upon the si-
milarity of properties which are distinct,
characteristic, and invariable.

The analysis of any substance contain-
ing mixtures of the different vegetable
principles, may be made in such a man-
ner as is necessary for the views of the
agriculturist, with facility. A given
quantity, say 200 grains, of the substance
should be powdered, made into a paste
or mass, with a small quantity of water,



SIR H. DAVY S AGRICULTURAL CHEMISTRY.



163



and kneaded in the hands, or rubhed in a
mortar for some time, under cold water;
if it contain much gluten, tliat principle
Avill separate in a coherent mass. After
this process, whether it has afiorded glu-
ten or not, it should be kept in contact
with half a pint of cold water for three or
four hours, being occasionally rubbed or
agitated: the solid matter should be sepa-
rated from the fluid by means of blotting
paper; the fluid should be gradually heat-
ed; if any flakes appear, they are to be
separated by the same means as the solid
matter in the last process, i. e. by filtra-
tion. The fluid is then to be evaporated
to dryness. The matter obtained is to be
examined by applying moist paper, ting-
ed with red cabbage juice, or violet juice,
to it: if the paper become red, it contains
acid matter; if it become green, alkaline
matter; and the nature of the acid or al-
kaline matter may be known by applying
the tests described, pages 149, 150, and
151. If the solid matter be sweet to the
taste, it must be supposed to contain su-
gar; if bitterish, bitter principle or ex-
tract; if astringent, tannin; and if it be
nearly insipid, it must be principally gum
or mucilage. To separate gum or muci-
lage from the other principles, alcohol
must be boiled upon the solid matter,
which will dissolve the sugar and the ex-
tract, and leave tlie mucilage; the weight
of which may be ascertained.

To separate sugar and extract, the al-
cohol must be evaporated till crystals
begin to fall down, which are sugar; hut
they will generally be colored by some
extract, and can only be purified by re-
peated solutions in alcohol. Extract may
be separated from sugar by dissolving the
solid, obtained by evaporation from alco-
hol, in a small quantity of water, and
boiling it for a long while in contact with
the air. The extract will gradually I'all
down in the form of an insoluble powder,
and the sugar will remain in solution.

If tannin exist in the first solution
made by cold water, its separation is
easily effected by the process described
pages 124 and 125. The solution of
isinglass must be gradually added, to pre-
vent the existence of an excess of animal
jelly in the solution, which might be mis-
taken for mucilage.



When the vegetable substance, the sub-
ject of experiment, will afford no more
l^rinciples to cold water, it must be ex-
posed to boiling water. This will unite
to starch if there be any, and may like-
wise take up more sugar, extract, and
tannin, provided they be intimately com-
bined with the other principles of the
compound.

The mode of separating starch is. simi-
lar to that of separating mucilage.

If after the action of hot water anything
remain, the action of boiling alcohol is
then to be tried. This will dissolve re-
sinous matter, the quantity of which may
be known by evaporating the alcohol.

The last agent that may be applied is
ether, which dissolves elastic gum, though
the application is scarcely ever necessa-
ry; for if this principle be present, it may
be easily detected by its peculiar quali-
ties.

If any fixed oil oi* wax exist in the ve-
getable substance, it will separate during
the process of boiling in water, and may
be collected.

Any substance not acted upon by wa-
ter, alcohol, or ether, must be regarded as.
woody fibre.

If volatile oils exist in any vegetable
substances, it is evident they may be pro-
cured, and their quantity ascertained, by
distillation.

When the quantity of fixed saline, al-
kaline, metallic, or earthy matter in any
vegetable compound, is to be ascertained,
the compound must be decomposed by
heat, by exposing it, if a fixed substance,
in a crucible, to a long continued red
heat; and if a volatile substance, bypass-
ing it through an ignited porcelain tube.
The nature of the matter so ])roduced,
may be learnt by applying the tests men-
tioned in pages 151 and 152. The only
analyses in which the agricultural che-.
mist can often wish to occupy himself,
are those of substances containing princi-
pally starch, gluten, sugar, oils, mucilage,
albumen, and tannin.

The two following statements will af-
ford an idea of the manner in which the
results of experiments may be arranged.

The first is a statement of the compo-
sition of ripe peas, deduced from experi-
ments, made by Einhof; the second are



164



DEFINITION OF TERMS.



of the products afforded by oak bark, de-
duced by experiments conducted by my-
self.

3S40 parts of ripe peas afford —
Of starch, - - - 1265 parts.
Fibrous matter analogous to
starch, with the coats of
the peas, ... 840 "
A substance analogous to glu-
ten, - - • - - 550 "
Mucilage, - - - 249 "

Saccharine matter, - - 81 "
Albumen, - - - 66 "

Volatile matter, - - 540 "
Earthy phosphates, - - 11 "

Loss, - - - - 229 "

1000 parts of dry oak bark, from a
small tree deprived of epidermis, con-
tain —

Of woody fibre, - _ _ 876
tannin, - - _ - 57

extract, _ - . . 31

mucilage, - - - - 18

matter rendered insoluble during
evaporation, probably a mixture
of albumen and extract, - 9

loss, partly saline matter, - 30



DEFINITION OF TERMS.

Letter L

Irnpelus, in mechanics, the force with
which one body impels or strikes an-
other.

Incline Plane, in mechanics, one that
makes an oblique angle with the horizon.

Incnrvation, of the rays of light,
their bending out of a rectilinear or
straight course, occasioned by refraction.

Induction, in logic, a conclusion from
the particular to the general. Strict
conclusions are made from the general to
the particular. The general premise be-
ing true, the application to the particular
case which is included in it follows with
logical certainty. Induction gives only
probability. If, for instance, we conclude,
from the earth being habitable, that the
other planets are so, the conclusion is on-
ly probable. Induction rests upon the
belief that general laws and rules ar^ ex-
pressed in the particular case; but a pos-
sibility always remains that these gene-
ral laws and rules are not perfectly
known. An induction may be perfect
or imperfect. To make it perfect, the



premises must include all the grounds
that can affect the result. If this is not
the case it is imperfect. For instance,
evei-y terrestrial animal lives, every serial
animal lives, every aquatic animal lives,
every reptile lives, therefore, every ani-
mal lives. If we now allow that there ex-
ists no animal not included in the four enu-
merated classes, the induction is perfect.

Inertia of matter, in philosophy, is
defined by Sir Isaac Newton to be a pas-
sive principle, by which bodies persist
in their motion to rest, receive motion
in proportion to the force impressing it,
and resist as much as they are resist-
ed. It is also defined by the same
author to be a power implanted in all
matter, whereby it resists any change
endeavored to be made in its state.

Inflection, or point of inflection, in
the higher geometry, is the point where
a curve begins to bend a contrary way.

Infusion. — A method of obtaining the
virtues of plants, roots, &c., by steeping
them in a hot or cold liquid.

Ink. — There are two principal kinds
of ink, writing and printing ink.

Writing ink. — When to an infusion
of gall nuts some solution of sulphate of
iron (green copperas) is added, a very
dark blue precipitate takes place. This
principitate is the gallic acid of the galls
united to the iron of the green vitriol,
forming gallet of iron, which is the basis
of writing ink. If galls and sulphate of
iron only were used, the precipitate
would fall down, leaving the water co-
lorless; and in order to keep it suspended
in the water, forming a permanently
black, or rather a very dark blue fluid,
gum arable is added, which, by its viscid
nature, prevents the precipitate from
falling down. Various receipts have
been given for the composition of writing
ink, but very few have been founded
upon a knowledge of its real nature.
The receipt given by M. Ribencourt is
as follows: Take eight ounces of Aleppo
galls, in coarse powder; four ounces of
logwood in thin chips; four ounces of
sulphate of iron, (green copperas;) three
ounces of gum arable in powder; one
ounce of sulphate of copper, (blue vi-
triol;) and one ounce of sugar-candy.
Boil the galls and logwood together in



DEFINITION OF TERMS,



165



twelve pounds of water, for one hour, or
till half the liquid has been evaporated.
Strain the decoction through ahairsieve,
or linen cloth, and then add the other in-
gredients, stir the mixture till the whole is
dissolved, more especially the gum, after
which, leave it to subside for 24 hours,
then decant the ink, and preserve it in
bottles of glass, or stoneware, well cork-
ed. The following will also make a
good ink: to one quart of soft water, add
four ounces of galls, one ounce of coppe-
ras roughly bruised, and two ounces of
gum arabic. Let the whole be kept near
the fire a few days, and occasionally well
shaken.

Red writing ink, is made in the fol-
lowing manner. Take of the raspings of
Brazel wood a quarter of a pound, and in-
fuse them two or three days in vinegar.
Boil the infusion for an hour over a gen-
tle fire, and afterwards filter it while hot.
Put it again over the fire and dissolve in
it, first, half an ounce of gum arabic and
after^vards of alum and white sugar, each
half an ounce.

Printing ink is a black paint, compos-
ed of lampblack and linseed or suet oil
boiled, so as to acquire considerable con-
sistence and tenacity. The art of prepar-
ing it is kept a secret, but the obtaining
of good lamp black appears to be the
chief difficult}^ in making it.

The ink used by the copper plate prin-
ters differs from the last only in the oil
not being so much boiled, and the black
which is used being Frankford black.

Sympathetic inks are such as do not
appear after they are written with, but
which may be made to appear at plea
sure, by certain means to be used for that
purpose. A variety of substances have
been used for that purpose; we will de-
scribe the best of them.

1. Dissolve some sugar of lead in water,
and write with the solution. When dry,
no writing will be visible. When you
want to make it appear, wet the paper
with a solution ofalkalinesulphuret (liver
of sulphur) and the letters will imme-
diately appear, of a brown color; even
exposing the writing to the vapors of
these solutions will render it apparent.

2. Write with a solution of gold in
aqua-regia, and let the paper dry gently



in the shade. Nothing will appear; but
draw a sponge over it wetted with a so-
lution of tin in aqua-rcgia, the writing
will immediately appear of a purple co-
lor.

3. Write with an infusion of galls, and
when you wish the writing to appear,
dip it into a solution of green vitiiol;
the letters will appear black.

4. Write with distilled sulphuric acid,
and nothing will be visible. To render
it so, hold it to the fire, and the letters
will instantly appear black.

5. Juice of leinons, or onions, a solu-
tion of sal-ammoniac, green vitriol, &c.,.
will answer the same purpose, though
not so easily, nor with so little heat.

6. Green sympathetic ink. — Dissolve
cobalt in nitro-muriatic acid, and write
with the solution. The letters will be
invisible till held to the fire, when they
will appear green, and will disappear
completely again, when removed into the
cold. In this manner they may be made
to appear and disappear at pleasure.

A very pleasant experiment of this
kind is to make a drawing representing
a winter scene, in which the trees appear
void of leaves, and to put the leaves on
with this sympathetic ink; then, upon
holding the drawing near to the fire, the
leaves will begin to appear in all the ver-
dure of spring, and will very much sur-
prise those who are not in the secret.

Blue sympathetic ink. — Dissolve co-
balt in nitric acid; precipitate the cobalt
by potass; dissolve this precipitated oxide
of cobalt in acetic acid, and add to the
solution one-eighth of common salt; this
will form a sympathetic ink, that, when
cold, will be invisible, but will appear
blue by heat.

On t/ie composition of a new Indeli-
ble writing ink, by Dr. Traill. — To pre-
pare the ink, the inventor directs that
the gluten of ivheat be separated from
the starch as completely as possible, by
the usual process, and when recent, to be
dissolved in pyroligneous acid with the
aid of heat; this forms a saponaceous
fluid, which is to be tempered with water
until the acid has the usual strength of
vinegar. He grinds each ounce of this
fluid with from eight to ten grains of the
best lamp black, and one and a half



166



DEFINITION OF TERMS.



grains of indigo. The following are the I tarous acids, in water, may be ap



qualities of this ink.

1st. It is formed of cheap materials.

2d. It is easily made, ihe coloring
matter readily incorporating with the ve-
hicle.

3d. Its color is good.

4th. It flows freely from the pen.

5th. It dries quickly



plied to the most delicate fabrics without
any danger of injuring them, and the
same solutions will discharge writing,
but not printing ink. Hence they may
be employed in cleaning books which
have been defaced by writing on the
margin without impairing the text. Le-
mon juice, and the juice of sorrel, will



6th. When dry it is not removable by also remove ink stains, but not so easily



friction

7th. It not aflected by soaking in
water.

8lh. Slips of paper witten on by this
ink have remained immersed in solutions
of chemical agents, capable of immediate-
ly effacing or impairing common ink,
for seventy-two hours, without change,
unless the solutions be so concentrated
as to injure the texture of the paper.
The author offers this composition as- a
writing ink, to be used on paper, for the
drawing out of bills, deeds, wills, or
wherever it is important to prevent the
alteration of sums, or signatures, as
well as for handing down to posterity,
public records in a less perishable mate-
rial than common writing ink. He con-
cludes his paper by stating, that should
it be found to present an obstacle to the
commission of crime; should it even in a
single instance, prevent the perpetration
of an offence so injurious to society, as
the falsification of a public or private
document, the author will rejoice in the
publication of his discovery, and consider
that his labor has not been in vain.

Edln. New. Phil. Journ.

To make India Ink, see page 6



as tiic concrete juice of lemons or citric
acid.

Inolithus, in mineralogy, a stone con-
sisting of carbonate of lime, carbonic acid
gas, and a little iron; entirely soluble in
nitric acid, with effervescence.

Inscribe, in geometry. A figure is
said to be inscribed in another, when all
its angles touch the sides or planes of the
other figure.

Insolation, in chemistry, a term made
use of to denote an exposure to the sun,
to promote the chemical action of one
substance upon another.

Insf.ruments, {viathematical.) A
pocket case of mathematical instruments
contains the following particulars, viz: 1,
A pair of plain compasses — 2, A pair of
drawing compasses, with its several parts
— 3, A drawing-pen and pointer — 4, A
protractor, in form of a sernicircle, or
sometimes of a parallelogram — 5, A pa-
rallel ruler — 6, A plain scale — 7, A sec-
tor, besides the black-lead pencil for
drawing lines.

Insurance, is a contract whereby, for
a stipiilated consideration, called a pre-
mium, one party undertakes to indem-
nify another against certain risks. The



To make Lithographic Ink, see page party undertaking to make the indemnity
15. I is called the insurer or underwriter, and

Ink, removing the stains of. — The; the one to be indemnified the a^^'wr^'c^ or
stains of ink on cloth, paper, or wooA insured. The instrument, by which the
may be removed by almost all acids; but contract is made, is denominated a policy.



those acids are to be preferred which are
least likely to injure the texture of the
stained substance. The muriatic acid,
diluted with five or six times its weight
of water, may be applied to the spot, and,



Integer, in arithmetic, a whole num-
ber in contradistinction to a fraction.

Internal, \n general, signifies whatever
is within a thing.

Euclid proves that the sum of the three



after a minute or two, may be washed angles of every triangle is equal to two
off, repeating the application as often as i I'ight angles; whence he deduces several
may be found necessary. But the vege-' useful corollaries. He likewise adduces
table acids are attended with less risk, j from the same proposition this theorem,
and are equally effectual. A solution of j viz: that the sum of the angles of every
the oxalic, citric (acid of lemons) or tar- 1 rectilinear figure is equal to twice as



URFINITIOX OF TERMS.



167



many right angles as the figure hath
sides, excepting or subtracting four.

Intersection, in the mathematics, sig-
nifies the cutting of one line or plane by
another: thus we say that the mutual in-
tersection of two planes is a right line.

Invention, in science, is distinguished
from discoveri/, as implying more crea-
tive combining power, and generally sig-
nifies the application of a discovery to a
certain purpose.

Involution, in mathematics, the rais-
ing of a quantity from its root to any
power assigned. Thus 2 X 2 X = 8.
Here S, the third power of 2, is found by
involution. By continuing the process,
we can obtain any power of 2, and so
with other numbers.

Iodine, the name of an undecompound-
ed principle or element in chemistry. It
had escaped the observation of chemists
until 1812, when a manufacturer of salt-
petre at Paris detected it in the ashes of
sea-weeds, in the following manner. In
evaporating the ley from these ashes, to
procure the carbonate of soda which they
contain, he noticed that the metallic ves-
sels with which he operated were power-
fully corroded, and that the corrosion was
increased as the liquor became more con-
centrated. Having at hand, one day, a
bottle of sulphuric acid, he added some
of it to a portion of the mother-water,
and was surprised to see a rich violet
vapor disengaged ; this vapor was the
iodine. Heat ond'e communicated the ob-
servation to M. Clement Desormes, who
sat about collecting some of the vapor,
and after examining its leading proper-
ties, announced it as a new body. Its
real nature was soon after unfolded
through the accurate researches of Gay
Lussac and Sir H. Davy. Its history
proved singularly interesting in modify-
ing the then prevailing theory of che-
mistry. Sir H. Davy had a few years
previously promulgated the new theory
of chlorine, which was still received with
suspicion among chemists. The strong
analogies, however, between this sub-
stance and chlorine, in their relations to
combustibles, both bodies forming com-
pounds by uniting with them, similar to
acids containing oxygen or oxides, were
conceived to give great weight to the



views of Sir H. Davy, and operated com-
pletely to overthrow the erroneous hy-
pothesis of oxygenation invented by La-
voisier. Its investigation, therefore, may
be said to have formed a new era in
chemistry. The physical properties of
iodine are as follows; it is a soft, friable,
opaque solid, cf a blueish black color,
with a metallic lustre, usually in scales,
but sometimes in distinct crystals of the
form of rhomboids, or rhomboidal tables,
referable to an octahedron, with a rhom-
bic base as their primary form; its spe-
cific gravity is 4.946. It ])Ossesses an
odor somewhat analogous to that of chlo-
rine. It is a non-conductor of electrici-
ty, and possesses in an eminent degree
the electrical properties of oxygen and
chlorine.

Iodine enters into fusion at 225° Fahr.,
and boils at 347°; but when moisture is
present, it sublimes rapidly at a tempera-
ture considerabl}' below 212°, and gives
rise to a dense vapor of the usual violet
hue. It is scarcely soluble in water, but
is readily taken up by alcohol and ether,
to which it imparts a reddish brown co-
lor. It extinguishes vegetable colors, but
with less energy than chlorine. It is not
inflammable. Its range of affinitj^ for
other bodies is very extensive; the most
important compounds it forms with these
we shall describe after alluding to its na-
tural state and preparation. It exists
most abundantly in the various species of
fucus, which form the greatest part of the
sea-weeds of our coast; it also occurs in
the sponge, and in the coverings of many
molluscous animals, and has been found
in a great nun^ber of mineral waters, as
those of Salz in Piedmont, Saratoga in
New York, &c., and more recently has
been detected in some silver ores from
Mexico, and in an ore of zinc from Up-
per Silesia. But it is from the incinera-
ted sea-weed, or kelp, that the iodine, in
large quantities, is obtained. As the soap
manufacturers are in the habit of obtain-
ing their soda from kelp, iodine may be
procured, very economically, from the
residuums of their operations, according
to the process invented by Di-. Ure, which
is as follows.

The brown iodic liquor of the soap-
boiler, or the solution of kelp from which



168



DEFINITION OF TERMS.



all the crystallizable ingredients have
been separated by concentration, is heat-
ed to about 230° Fahr., poured into a
lirge stone-ware basin, and saturated with
diluted sulphuric acid. When cold, the
liquor is filtrated through woollen cloth,
and to every 12 oz. (apothecaries' mea-
sure) of it, is added 1000 grains of black
oxide of manganese in powder. The
mixture is put into a glass globe, or large
matrass with a wide neck, over which a
glass globe is inverted, and heat is ap-
plied, which causes the iodine to sublime
copious!}', and to condense in the upper



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