Boekgegevens
Titel: First English reading book: Engelsch leesboek voor instituten, gymnasiën en hoogere burgerscholen: met Nederlandsche woordenlijst
Auteur: Herrig, Ludwig
Uitgave: Arnhem: J. Voltelen, 1869 *
Auteursrechten: Zie auteursrechten
Citeerinstructie: Bijzondere Collecties van de Universiteit van Amsterdam, UBM: IWO 513 H 21
URL: https://schoolmuseum.uba.uva.nl/bookid/LCSM_204683
Onderwerp: Taal- en letterkunde naar afzonderlijke talen: Engelse taalkunde
Trefwoord: Leesvaardigheid, Engels, Leermiddelen (vorm)
* jaar van uitgave niet op de gebruikelijke wijze verkregen, mogelijk betreft het een schatting
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•189
colour. It is used for the backs of chim-
nies, grates, boilers, pipes, rail-roads, com-
mon cannon balls, &c.
Cast iron is converted into wrought iron
by a process called blooming; it is thrown
into a furnace and kept melted by fire, it
remains in this situation for about two
hours, a workman being continually em-
ployed in stirring it, until, notwithstanding
the heat to which it is exposed, it acquires
by degrees consistency and tenacity, and
congeals into a mass which is become mal-
leable. It is taken out of the furnace
whilst hot, and violently beaten by a large
hammer, worked by machinery; in this
manner it is formed into bars of iron. The
value of wrought iron in machinery, and
tools of all descriptions, is incalculable.
Steel is prepared from wrought iron in
the following manner. The bars of iron are
kept in contact with ignited charcoal for
several hours in earthen crucibles, from
wliich the air is excluded. Steel, if heated
to redness, and then suffered to cool slowly,
becomes soft and pliable, if plunged while
hot into cold water, it is rendered suscep-
tible of a high polish, and acquires such
extreme hardness as even to scratch glass,
while at the same time it becomes elastic
and brittle. Its softness and ductiUity may
however be restored by heating it again
and cooling it slowly. Steel varies in co-
lour under the influence of heat, first it as-
sumes a straw colour, then a light yellow,
purple, violet, red, deep blue succeeds, and
last of all a bright blue. These hues in-
dicate the different tempers which steel ac-
quires, from that proper for common files,
to that requisite for the finely elastic springs
of watches. Steel is used for al kinds of
edged tools, in which keenness is necessary
it is also much employed for ornamental
purposes, on account of the elegant pohsh
which it is capable of taking.
Iron is very valuable from the magnetical
properties it may acquire. Cy these it en-
ables the mariner to steer across the ocean,
the traveller to direct his course with safety
in the pathless desert, and the miner to
guide his researches after subterranneous
treasures. The loadstone or natural mag-
net, is an oxide of iron; it communicates
its powers to bars of iron or steel, when
placed in contact with them. The artificial
magnet is now always used; as it possesses
and retains all the properties of the load-
stone. The qualities which render it use-
ful, are, its attracting iron; and its polarity,
or the power by which it points to the
poles when freely suspended. One end in-
variably turns to the North, and the other
to the South, except when it approaches
the pole; there the directive power ceases
altogether, which circumstance constitutes
one of the great difficulties in navigating
the Arctic Sea's.
Iron is the most universally diffused of
the metals. It is found every where, in
greater or less quantities; but England,
France, Sweden, and Russia, are richer in
this metal than the other countries of Eu-
rope. It is very rarely met with in a na-
tive state, but generally as an oxide, or in
combination with Sulphuric or Carbonic
Acid.
148. TIN.
Tin is chiefly employed in the manufac-
ture of culinary utensils; they are not how-
ever made of solid tin, but of what is call-
ed tin-plate, which is thus prepared. Thin
iron plates are first cleansed completely, by
washing them in water and sand; they are
then dipped into melted tin, afterwards
steeped in water acidulated with sulphuric
acid. This process causes the tin not only
to cover the surface of the iron plate, but
to penetrate it so that the whole mass be-
comes of a whitish colour.
Native Tin is never found, and its ore is
of less common occurrence than that of
iron. England, Germany, Chili, and Mexico,
produce the largest quantity of this metal.
The tin mines of Cornwall were well known
to the ancients; and the Phoenicians are
said to have traded with the Britons for it
long before the birth of our Saviour. It
is always found as an oxide, or mixed with
sulphur and copper. It occurs chiefly in
veins running through granite and other
rocks. When it is taken from the mine, it
is broken into small pieces, and streams of
water passed over it, to free it from the
earthy particles with which it is intermixed;
it is then roasted and smelted, when the
metal is poured out into quadrangular
moulds of stone, and receives the name of
block tin. The arms of the Duke of Corn-
wall are stampt upon it while in this state,
and a large portion of the income of the
Prince of Wales, who holds the title, is
derived from the duty paid upon it.
149. COAL.
Coal may be considered as a mineral,
both from its subterraneous situation, and
the quahties which it possesses; many cir-
cumstances however justify the now preva-