STEEL. 
steel. In an elaborate dissertation by Monge, 
_Berthollet, and Vandermonde, it is asserted that 
good hammered iron consists of zon free from 
all heterogeneous matter; that steel is a combi- 
nation of iron and carbon ; and that cast-iron is 
a combination of iron with carbon, in which the 
proportion of carbon is greater, and the iron not 
wholly free from oxygen. Dr. Thomson gives 
the following as the composition of cast-steel :— 
Tron, ; 5 : . : 99 
Carbon, with some silicon, é : 1 
100 
It is a very desirable thing to combine the ex- 
treme hardness of steel with the toughness and 
tenacity of iron. This is done by welding them 
together. It isin this way that edge tools are 
made. A bit of steel is welded to the iron on 
that side of the plate or bar which is to be 
worked into an edge; or the surface of a piece 
of iron is converted into steel by cementation, 
and the process is stopped before the carbon 
penetrates so far as to convert the whole piece 
into steel. This is called case-hardening. The 
piece of work, when nearly finished, is covered 
with a paste made of combustible matter. Cer- 
tain animal substances, as horns and_ hoofs, 
chopped hair, bone, shavings, &c., are made up 
into a paste. The iron is covered with it, and 
the whole wrapped up in clay. This is first 
dried and hardened before the fire, and then put 
into a forge, and kept in a low red heat for an 
hour or two. When taken out, the surface is 
converted into steel. In this way almost all the 
parts of gun-locks are treated. Besides the super- 
ficial hardness that they thus acquire, it is well 
known that they have much less friction than 
while in the state of iron,and they are much less 
liable to rust. Every kind of iron is not suited to 
the manufacture of steel. English iron does not 
answer at all. The iron which answers best is 
made at Danemora, in Sweden, from the magne- 
tic iron ore. The whole of the yearly produce of 
the Danemora mines, amounting to 8,000 tons, 
is imported into Britain, and converted into 
steel, | 
The natural steel, or German steel, is an impure 
and variable kind of steel, procured from cast- 
iron, or obtained at once from the ore. It is 
much cheaper than the cementation steel. It 
has also the property of being easily welded, 
either to iron or to itself. Its grain is unequally 
granular, sometimes even fibrous; its colour is 
usually blue; it is easily forged; it requires a 
strong heat to temper it, and it then acquires 
only a middling hardness. When forged re- 
peatedly, it does not pass into iron so easily as 
the other kinds. The natural steel yielded by 
cast-iron, manufactured in the refining houses, is 
known by the general name of furnace steel; and 
that which has only been once treated with a 
refining furnace, is particularly called rough steel, 
a a frequently very unequally converted into 
STELIS. 337 
steel. The best cast-iron for the purpose of mak- 
ing natural steel, is that obtained from the brown 
hematite, or from the sparry iron ore. If it 
contains manganese, this is thought to be an 
advantage. It should be of a grey colour. White 
cast-iron does not yield steel, unless its charge of 
carbon is increased, either by stirring the melted 
metal with a long pole, and keeping it melted a 
long time, that it may absorb charcoal from the 
lining of the furnace, or by melting it with dark- 
coloured iron. Black cast-iron yields a bad, 
brittle steel, unless the excess of carbon that it 
contains is either burnt away, or it is mixed 
with finery cinder. The cast-iron to be converted 
into steel is then melted in blast furnaces, and 
treated nearly the same as if it were to be re- 
fined into bar-iron, only the blast 1s weaker; the 
tewyre, instead of being directed so as to throw 
the wind upon the surface of the melted metal, 
is placed nearly horizontally ; the melted metal 
is kept covered with slag, and is not disturbed 
by stirring. When the iron is judged to be suf- 
ficiently refined, and is grown solid, it is with- 
drawn from the furnace and forged. The natu- 
ral steel made directly from the above-mentioned 
ores, in small blast furnaces, is a good steel for 
ploughs and similar machines: the best of it is 
excellent for sawsand cutlery. The most esteemed 
steel of this kind comes from Germany, and is 
made in Styria. It is usually sold in chests or 
barrels, two and a half or three feet long. 
STEELYARD. A balance for determining the 
weight of bodies by means of a single standard 
weight. See the article Batance. Ruthven’s 
steelyard, invented upwards of 20 years ago, by 
Mr. John Ruthven of Edinburgh, is well suited 
to the use of farmers and of persons who deal in 
farm-produce. It comprises a longer arm, a 
shorter arm, a weight moveable along the for- 
mer, a scale suspended to the latter, a rod with 
looped vertical uprights in the ends for suspend- 
ing and confining the arms, and a stand for sup- 
porting and poising the whole machine. The 
longer arm has so limited a range of motion at 
its extremity as to prevent the jerks and long 
vibrations to which common steelyards are sub- 
ject ; the weight cannot escape at either extremity 
of the arm, and consequently can never be mis- 
laid or lost; and the scale is ingeniously con- 
trived to open one end and discharge its contents 
at a touch, and is therefore very convenient for 
weighing grain, flour, small seeds, and similar 
commodities. 
STEEP. Any saline or medicated liquid for 
the immersion of seed-corn preparatorily to its 
being sown. See the articles Srep, Smut, and 
WHEAT. 
STEER. A young bullock. 
STEG. A gander. 
STELIS. A genus of tropical epiphytous 
plants, of the orchis family. Four or five spe- 
cies have been introduced to British collections, 
—but, as compared with other orchidacee, are 
Y 
