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Norman Allison Calkins.

Manual of object-teaching : with illustrative lessons in methods and the science of education online

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salt is manufactured are those at Salina and Syracuse, in the State
of New York. These springs furnish from 5,000,000 to 6,000,000
bushels of salt each year. The most extensive salt-mines are
those of Poland, Europe, which are supposed to embrace a bed of



SUGGESTIONS FOR LESSONS. 151

solid salt 500 miles long, 20 miles wide, and 1200 feet thick. The
excavations are so long and wide that houses, stables, storehouses,
churches, and streets are cut out of solid salt. In the chapels ev-
erything is made of the rock-salt walls, doors, altars, crucifixes,
pedestals, and statues. The air in these mines is dry, and free
from bad gases, and everything is kept in a perfect state of pres-
ervation. These mines have been worked many hundreds of years.

In the interior of Africa salt is not commonly found by the
natives, and they will sell a slave for a handful of salt. ^ The chil-
dren there suck pieces of salt with as much delight as boys and
girls do their sticks of candy in this country.

Among the Arabs and Turks salt is a 'symbol of fidelity. A
man who has partaken of salt with an Arab is bound to him by
the laws of hospitality, and is treated as a friend.

To which kind of substances does salt belong ?

Write all you can remember about salt; its kinds, its uses;
how obtained ; where found ; shape of its crystals ; about its sol-
ubility ; its chemical composition and name; about the salt-mines
of Poland ; its scarcity in Africa ; its symbol of fidelity, and other
facts.

SODA.

How Obtained. Soda was formerly obtained from the ashes
of marine plants. It is now manufactured from common salt by
the use of acids, charcoal, lime, heat, and water. Large manufac-
tories are engaged in the process of compelling salt, by the aid of
the above agents, to lose its saltness and become the common soda
so extensively used for cleaning purposes, for making soap, and in
the manufacture of glass.

Carbonate of Soda. This form of soda, sometimes called
" washing-soda," is known to the chemist as carbonate of soda ;
this is used in making soap.

Bicarbonate of Soda, or hydro-sodic carbonate, is produced by
combining carbonic-acid gas with carbonate of soda. This form
of soda is used in bread-making, and in the blue papers of Seidlitz-
powders ; the white papers contain tartaric acid. Bicarbonate of



152 MANUAL OF OBJECT-TEACHING.

soda contains twice as much, carbonic acid as the carbonate of soda
has. It is the escape of the carbonic acid which causes the effer-
vescence produced by these soda powders.

Write about soda its uses ; how made ; different kinds, etc.
and state whether it is a vegetable or a mineral substance.

SOAP.

Uses. When you wash your hands in the play-ground, can
you make them as clean as when you wash them at home ? Why
not ? Why is soap used ? When is soap used ? Who uses soap
for washing clothes ?

What other substances are sometimes used in washing clothes ?
Why are soda and borax used in washing clothes ?

Qualities. When soap is put in the water and rubbed about,
what happens to the soap? It melts. What quality has any-
thing that dissolves in water ? What change is made in the ap-
pearance of the water by the soap ? How does water feel that
has had soap dissolved in it ?

How Soap is Made. Soap is made of fat, or oil, and an al-
kali. Potash and soda are alkalies. An alkali made by soaking
wood-ashes in water is called lye. An alkali has an acrid, hot,
and disorganizing nature. Carbonate of soda is not so strong an
alkali as potash, and is less liable to produce injury.

The alkali decomposes the fat or oil, sets free the glycerine of
the oil (which dissolves in water), and the fatty acid unites with
the alkali and forms the soap. The alkali is the chief agent in
cleansing.

Kinds of Soap. The kinds of soap named from their condi-
tion are hard soap and soft soap. Soft soaps are made by using
potash or lye as the alkali. Hard soaps are made by using soda
as the alkali. Tallow will make a harder soap than oil.

Common Bar Soap is made from fat, soda, and resin.

Castile Soap is made from olive oil and soda, and colored by
an oxide of iron.



SUGGESTIONS FOR LESSONS. 153

Fancy Soaps are essentially common soaps mixed with differ-
ent aromatic oils and coloring substances.

Soap cleanses dirt from clothes by the alkali in the soap dis-
solving the oily, greasy portion of the dirt, and thus setting the
whole free. The ancient Gauls made soap of ashes and tallow.
Why did they use ashes ?

Now write on your slates all you can remember about soap ;
how made, kinds, qualities, uses, etc.

CANDLES.

Call attention to the use of candles ; where used ; when used ;
other substances used to give light. Show a candle ; let pupils
point out and name its parts. "Wick, made of loosely twisted
cotton, extending lengthwise through the middle of the candle.
Tallow, the yellowish -white substance around the wick, which
melts wlien the candle is lighted, flows up the wick, burns, and
makes the light. Shape of the candle cylindrical ; one end flat
and circular, the other end tapering and conical.

"What Candles are Made from. Candles are made of tallow,
spermaceti, wax, stearine, and paraffine.

How Tallow -candles are Made. Tallow - candles are some-
times made by dipping the wicks into melted tallow many times,
allowing the tallow to harden after each dip. These are known
as dipped candles. They are also made by pouring melted tallow
into moulds in which the wicks have been fastened, and allowing
it to cool. These are known as mould candles. Candles com-
posed of other substances than tallow or wax are generally made
in moulds.

"Wax -candles are made by suspending the wicks over the
melted wax, and pouring the wax repeatedly over the wicks until
they attain the desired size.

Spermaceti is a white, semi-transparent substance found in the
head of the sperm-whale.

Wax, the substance made by bees from which the comb is

7*



154 MANUAL OF OBJECT-TEACHING.

formed. This is melted and strained to form wax for candles.
Wax-candles are the most expensive of all kinds of light.

Stearine, or Stearic Acid, is one of the solid substances ob-
tained when fats are decomposed by a chemical process. It does
not feel greasy, is firm, dry, and makes an excellent candle.

ParafSne is a white, waxy, inodorous, tasteless substance, ob-
tained from distillation of resinous or bituminous materials. It
is obtained from oil of tar. It readily combines with wax, sper-
maceti, or stearine ; and when used for making candles, it is mixed
with one of these substances to render it easier to melt by the
heat of the burning candle.

The illuminating power of gas is estimated by the number of
burning candles that its light equals. The gas-light of one burn<
er generally equals the light of fifteen or twenty candles.

Now write what you can remember about candles of the ma-
terials from which they are made ; how candles are formed ; the
kinds of candles used ; about gas-light as compared with candle-
light ; and any other facts.

PUTTY.

Can you tell me what holds the glass in a window ? Who
uses putty ? Is it used for other purposes than to hold glass in
windows ?

Qualities. Its color is a dull white, somewhat like dough. It
feels soft and greasy. It can be pressed into any shape.

It is adhesive sticks to glass, wood, or any substance.

It hardens in air the older the putty, the harder it becomes.

It is impervious to water, and thus keeps the rain from coming
through windows at the edges of the glass.

How Made. It is made of whiting (a finely-ground chalk)
and boiled linseed-oil, kneaded into a doughy mass and beaten
with a mallet.

CAMPHOR.

Take this vial, smell the liquid in it, and tell its name. Now
take this semi-transparent gum ; notice its soft feeling and its



SUGGESTIONS FOR LESSONS. 155

odor, and tell me whether it smells like the liquid in the vial.
What is it ?

The liquid camphor which you see used at home is made by
dissolving camphor-gum, like this piece shown you, in alcohol.

Where Found. The camphor-gum is obtained from the cam-
phor-tree, which grows most abundantly on the islands of Su-
matra, Borneo, and Formosa. This tree often attains the height
of one hundred feet, and is from six to ten feet in diameter. The
camphor-gum is found in masses, and is obtained by splitting the
trunk in pieces and picking out the lumps with a pointed instru-
ment. Some lumps have been found as large as a man's arm ;
and some trees yield twenty pounds of gum ; but commonly not
more than half of this amount is found in one tree. Camphor
is also obtained by distilling the chipped wood, and then collect-
ing the gum from the liquid.

Camphor-gum is soft, friable, and tough ; very volatile, inflam-
mable, fragrant, with a strong odor, and is soluble in alcohol.
When taken in large doses, it is fatally poisonous. It is also
destructive to insects.

The wood of the camphor-tree is valuable for making boxes
and trunks, which will protect clothing kept in them from insects.

Write a description of camphor its qualities, uses, where ob-
tained, etc.

WHALEBONE.

Teacher. What have I in my hand ? What can I do with this
piece of whalebone ? Can you name any of the qualities that
make whalebone useful ?

Pupils. It is tough, fibrous, flexible, light, and elastic.

T. [Shows the pupils a piece of a cow's horn, a piece of bone
and of whalebone. They examine each, after which the teacher
asks :] Which of these two substances, the horn or the bone, does
the whalebone most resemble ?

P. The horn.

T. That which we call whalebone is not a true bone ; it is not
a part of the common bones in the body of the whale. It is



156 MANUAL OF OBJECT-TEACHING.

found in the mouth of the Greenland whale. It is a horny sub-
stance, composed of many layers of fibrous plates, which form
a compact mass where they are attached to the upper jaw ; but
as they extend downward from six to twelve feet, they become
divided into coarse, loose fibres, forming a fringe-like enclosure
along the sides of the mouth. This fringe does not extend across
the front of the mouth. There are about three hundred of these
blades on each side of the mouth, each of which is from eight to
twelve inches wide at its root, and from one to two inches thick.
About one ton of whalebone is sometimes obtained from the
mouth of a single whale. It varies in quantity and length ac-
cording to the size of the animal.

Its Use to the Whale. The food of this whale consists of
small shrimps, crabs, fishes, mollusks, and other soft-bodied animals
which congregate in shoals of millions in the waters frequented
by the Greenland and other whales of this kind. The whale feeds
by swimming through shoals of these minute animals with its
capacious mouth open, allowing the sea-water, swarming with its
food, to pass in and flow out through the back and sides of the
mouth ; but the multitudes of small animals are retained in the
mouth by the great fringe strainer of whalebone ; thus the whale
is enabled to capture its prey by means of the great whalebone
fringes which line its mouth.

Its Uses to Us. Whalebone may be softened by boiling it,
and then it can be cut easily into such shapes as are needed for
its various uses. On cooling, it becomes harder, and of a darker
color than before boiling. It is used for stretchers of umbrellas
and parasols ; it is split into fibres and used for brushes, in place
of coarse bristles ; for framework of bonnets ; for stiffening stays
and waists of dresses; for whip-handles, and various other pur-
poses in which elasticity is a needed property.

Since the capturing of whales for their oil has diminished so
greatly, whalebone has become scarce and dearer.

Write all you can about whalebone; what it is ; where it is ob-
tained ; its use to the whale ; its value and uses to us ; its quali-
ties, etc.



NOTES OF LESSONS. 157



NOTES OF LESSONS.

COTTON.

Its Uses. For thread ; for various kinds of cloth as sheet-
ing, drilling, jean, cotton or Canton flannel, gingham, calico, chintz,
muslin, tarlatan, lace, hosiery, paper.

What is Cotton? A soft, downy substance resembling very
fine wool, which grows in pods of the cotton-plant in warm coun-
tries.

How it is Obtained. The seeds of the cotton-plants are sown
in rows, four or five feet apart, late in March or in April. The
plants generally grow from four to six feet high. The blossoms
are of a pale yellow or a faint purplish color. The pods contain-
ing the cotton fibre ripen and burst open in August and Septem-
ber, after which the cotton is picked from the plant.

The cotton seeds adhere to the cotton fibre when it is picked,
and the first step toward manufacture consists in separating the
seeds from the fibre. This is done by a machine called a cotton-
gin. After this process the cotton is packed in bales of several
hundred pounds each, and sent to market, from whence it is taken
to manufactories to be spun into yarn, and woven into different
kinds of cotton goods. Where is the cotton raised in the United
States taken to be manufactured ?

Qualities that make Cotton Useful. Its fine, long, and strong
fibres. The long and strong fibres make the thread and cloth
strong. Its fine, strong fibres make excellent thread. Its fibre
is not as strong as that of flax.

"Where Cotton is Raised. In the warm portions of the United
States, West Indies, South America, Africa, India, and China. It
is most extensively raised in the United States.

Require the pupils to write out a statement of all the important
facts presented in this lesson, and to read the statements before
the class. Proceed in the same manner with each of the succeed-
ing lessons.



158 MANUAL OF OBJECT-TEACHING.

FLAX.

What is Flax ? The strong fibre of an annual plant, with a
slender stalk, which grows from two to three feet high, covered
with a strong, fibrous bark. The seed of the flax-plant is sown
in the spring ; the plant bears small, blue blossoms in June and
July, and is ready for gathering in August which is done by
pulling it up by the roots and tying it in small bundles.

How Flax is Obtained. The small bundles of the plant are
placed on wet meadows, or under water, where* the gluten is soak-
ed out, and the woody stem becomes brittle by partially rotting.
The plant is afterward dried, then the woody stems are broken by
a machine and beaten out. The fibre is then combed by draw-
ing it over an instrument with long iron teeth, or spikes, set in
a board, which forms a sort of comb, called a hatchel or hacJde.
By this combing process the coarser fibres are separated from the
fine and soft ones, and the flax is made ready for spinning.

Uses of Flax. It is used for strong thread for sewing cloth,
carpets, and leather, for fish-lines, cords, and for linen goods.

Names of Goods made from Flax. Linen thread, tape, dam-
ask, white linen, brown linen, cambric, lawn, towels, handkerchiefs.

Qualities that make Flax UsefoL Its fibre is very long, strong,
and durable.

"Where it is Raised. It is grown most extensively in Ireland,
but is also raised in Scotland, England, Holland, France, Belgium,
Russia, and other portions of Europe ; also in the United States.

HEMP.

What is Hemp ? The hemp-plant is native of Asia, but is ex-
tensively cultivated in Russia, and is grown also in other parts of
Europe and in the United States. The plant is an annual, which
grows to the height of five or six feet. Hemp is the fibre of this
plant. It is coarser and stronger than that of flax. If carefully
examined, it will be seen that each coarse fibre is composed of
several minute ones twisted spirally.



NOTES OF LESSONS. 159

How it is Procured. The hemp -is obtained by rotting the
woody stem of the plant, breaking it, and then beating it out,
much in the same manner as is done with flax.

What is Made of it ? Cords, ropes, and cables ; sacking, and
various kinds of coarse, strong cloth.

WOOL.

"What is Made of Wool. Yarns, worsteds, flannels, blankets,
shawls, broadcloth, tweed, and other kinds of cloth ; merino, car-
pets, rugs, mats, drugget, baize, hosiery, felt, and many other arti-
cles of woollen goods.

What is Wool ? By the term wool is commonly meant the
fleecy covering of sheep, which is sheared from them early in
summer. This name is also given to the covering of some kinds
of goats, as the Cashmere and Angora goat, of Asia ; and to the
Llama and Guanaco of South America. The Cashmere goat has
a double covering one of long, coarse hair, and underneath this
one of fine, soft wool, from which expensive shawls are made.
The wool of the Alpaca Llama is fine, silky, and long. It is used
for alpaca goods and other materials.

Wool is raised in nearly all countries. The most extensive
manufactories of cloths and other woollen goods are in England,
France, Germany, and the United States.

What kind of a substance is wool ?

SILK.

Its Uses. It is used for sewing-silk, ribbons, handkerchiefs,
dress-silk, satin, velvet, curtains, furniture-covering, hosiery, gloves,
gauze, crape.

What is Silk ? Silk is the fine glossy web of the silk-worm.
It is stronger than the web of the spider. The silk-worm spins
this web around itself, in the form of a hollow case called a co-
coon, before changing into a moth. The cocoons are about one
inch long, and two-thirds of an inch thick. What kind of a sub-
stance is silk ?



ICO MANUAL OF OBJECT-TEACHING.

About the Silk-worm. The silk-worm is an insect in the
form of a caterpillar. It is hatched, by the warmth of the sun,
from an egg about the size of a pin-head ; and it attains the full
size two to three inches long in about eight weeks. During
this time it changes its skin four or five times. As the old skin
becomes too small, it bursts near the head, and the caterpillar
crawls out with a new dress. At each change of its skin the size
increases.

The silk-worm feeds on mulberry-leaves while it is growing.
After eating and growing for about eight weeks, the worm stops
eating and begins to spin, and continues spinning for about five
days. While spinning, it moves its head from side to side, as if
winding the fine silk about ; and the worm grows shorter as it
spins, and winds itself inside of the cocoon.

It next changes into a chrysalis, in a dark-brown case, within
the cocoon. In this condition it remains torpid for two or three
weeks ; then it changes into a moth, makes a hole in the cocoon
by softening the threads with a fluid, comes out, lays eggs, and
soon dies.

How Silk is Obtained. In about ten days after the cocoons
are finished, the insect must be killed, to prevent it from making
a hole in the cocoon, and coming out in the form of a moth. To
do this they are placed in a heated oven before the time for the
chrysalis to change to the moth, and thus the insect is killed.

The cocoons are next put in hot water, which dissolves the gum
and loosens the thread. The whole is now stirred with a bunch
of twigs, which catch the loose ends of the threads. Several of
these are taken together, to make them strong enough to handle
and wind upon a reel. The silk is taken from the reel, and tied
up into hanks ready for the manufacturer. In this state it is
called raw silk. These hanks of raw silk are placed on a six-sided
reel, or swift, and wound on bobbins. The silk is now sorted ac-
cording to its fineness and quality, and then is ready for spinning
or twisting.

This raw silk is sent to a mill, where two or more threads are
twisted together, and prepared for weaving and other purposes.
Manufacturers usually purchase silk in the raw state.



NOTES OF LESSONS. 161

Before the silk is ready for weaving it must be cleansed by
boiling it in soapy water. The color is now yellow. To make
silk white, it must be bleached ; to give it other colors, it must
be dyed.

The web of a single cocoon is from three to five hundred yards
in length. About one pound of good raw silk is obtained from
twelve pounds of cocoons.

Where Silk is Raised. Silk is raised in China, Japan, and
some other places in Asia ; in Italy, France, and other countries
of Europe ; in South America, and in many parts of the United
States. Silk goods are most extensively manufactured in France.

Articles Made of Silk. Silk for sewing; twist for button-
holes ; ribbons ; silks, plain, figured, etc. ; satin, crape, velvet,
gauze, handkerchiefs, shawls, stockings, gloves, poplins, etc.

LEATHER.

Its Uses. Leather, in different forms, is used for making boots,
shoes, gloves, mittens, harnesses, trunks, valises, book-binding, cush-
ions ; seats for chairs, cars, and carriages ; covers for carriages ;
cases, belts for machinery, washers, hose for fire-engines ; parch-
ment, on which valuable documents were formerly written.

Kinds of Leather. Calf-skin, kip, cow-hide, morocco, patent-
leather, kid, Russia-leather, harness-leather, sole-leather, sheep-skin,
buck-skin, seal-skin, dog-skin, vellum, parchment.

From what the Kinds of Leather are Made. Calf- skin is
made from the skins of calves not more than six months old ;
kip leather, from the skins of young cattle, older than calves;
cow - hide, from the skins of young cows; sole -leather, from the
skins of the ox, also of the old cow ; morocco, from the skins of
goats ; kid, from the skins of kids that are killed when too young
to eat grass ; patent-leather, a kind of leather covered with a japan
that gives it a smooth surface and a permanent polish ; Russia-
leather is made from the skins of calves, cows, goats, sheep, etc.,
by a special process of tanning, in which are used willow-bark,
red sandal-wood, and an oil, prepared from birch-bark, that im-
parts to this leather its peculiar odor, and renders it repulsive to



162 MANUAL OF OBJECT-TEACHING.

insects ; sheep-skin, made from the skin of the sheep ; buck-skin,
from the skin of the deer ; dog-skin, from the skin of the dog ;
seal-skin, from the skin of the seal ; harness-leather, from thick
ox-hide ; parchment, from the skins of sheep and goats ; vellum,
from the skin of young calves, tanned in nearly the same manner
as parchment.

How Common Leather is Tanned. The process of tanning
implies saturating the skins of animals with an astringent vegeta-
ble substance, called tannin, so thoroughly that it becomes insolu-
ble, and incapable of putrefaction.

Skins are prepared for tanning by first soaking them in lime-
water, to loosen the hair and the outer membrane ; then they are
scraped, to remove the hair and the hard cuticle ; then soaked in
an alkali, to remove the lime; next they are soaked in a weak so-
lution of sulphuric acid, which opens the pores of the skin and
prepares it to receive the tannin more rapidly. At this stage of
the process the skins, which are now called pelts, are placed in
pits, or tan-vats, with layers of ground tan-bark between them,
and the vat is filled with water. The skins are allowed to soak
in this manner for several months. Sometimes the vats are emp-
tied, and the hides placed in the vat again with fresh tan-bark.
The best leather is prepared by allowing the hides to soak thus
for about two years. Slow tanning makes the leather soft.

By means of the astringent property in the liquid in which the
skins are soaked, they become thicker and firmer, and the pores so
closed that water does not easily affect the leather. Scraping the
leather makes it of uniform thickness; rubbing and oiling it makes
it pliable and soft.

How the Tannin is Obtained. The astringent property in
which the skins are soaked the tannin is obtained chiefly from
oak-bark and hemlock-bark. Hemlock-bark is more commonly
used in this country, and oak-bark in Europe. Hemlock-tanned
sole-leather is of a darker color than the oak-tanned.

A cord of hemlock-bark will tan about five hides ; and it takes
the bark of two or more trees to make a cord. The acorn cup
and ball of the burr oak of the United States, if collected annu-



NOTES OF LESSONS.. 163

ally, would supply taunin for all the hides in this country, and
save the great destruction of trees to procure bark for this
purpose.

What qualities make leather useful for shoes ?

"What kind of a substance is leather ?

INDIA-RUBBER. .

Its Uses. For making overshoes, boots, soles of boots, sus-
penders, tape, cord, braces, bands, rings, air cushions and pillows,
life-preservers, beds, springs for doors, bearers for springs on rail-
road cars, bands, balls, tubes.

It is dissolved and spread on cloth for water-proof garments.

It is mixed with pitch, sulphur, etc., and made into a hard sub-
stance, from which combs, knife-handles, cups, and other articles



Online LibraryNorman Allison CalkinsManual of object-teaching : with illustrative lessons in methods and the science of education → online text (page 12 of 35)