34r8 
[September, 
AMERICAN AGrKICULTUEIST. 
separating it from the ore, it lias combined with some of 
the carbon or coal used in the furnace, and when it melts 
and runs from the furnace, it is a compound of iron and 
carbon; the amount of carbon varies from two to five 
per cent, i. e., in every hundred pounds of iron, there are 
from two to five pounds of carbon, and it is this which main¬ 
ly makes the iron brittle, and also allows it to be melted ; 
I say “ mainly” becanse there are impurities in the ore 
which affect the quality of iron, but we need not talk of 
them now. This brings us to the real difference between 
cast and wrought iron—cast iron contains carbon, and 
wrought iron does not. To get wrought iron, then, we 
must get rid of the carbon, and how do you suppose this 
is done? By burning it out. You know that coal is car¬ 
bon, and that it will burn, but the carbon in the cast iron 
is so mixed with the iron that it is difficult and slow to 
burn out. To make wrought iron, the pigs of cast iron 
are put into a very different kind of a furnace from the 
one used in melting cast iron ; it has a broad hearth, 
and is so built that the flame will play down upon 
it, and a plenty of air will pass in also. Here the iron 
melts on the floor of the furnace, and as the flames 
rush over it they burn out the carbon ; the iron is stirred 
now and then, and when it gets thick and pasty, and does 
not run any more, it is made into lumps or balls, and 
taken to the squeezer, a big hammer, which pounds the 
lump, and squeezes out any impurities, which remain 
melted while the pure iron is only pasty. This operation 
is called puddling, and the lumps are blooms. If we com¬ 
pare this iron with cast iron, we shall see how very dif¬ 
ferent they are. No matter how small a piece you take, 
you will not he very likely to break it, but if you ham¬ 
mer at a piece it will spread, or in other words it is mal¬ 
leable, while cast iron will break instead. Then it is 
very difficult to melt wrought iron, so much so that it is 
not worked in that way. It is also very different from 
cast iron, from the fact that it can be welded. 'When 
heated very hot—white hot—wrought iron becomes very 
soft and pasty, and when a smith wishes to join two 
pieces, he puts both in the fire and heats them to this 
pasty state; he then puts them together on his anvil, and 
hammers them so that the two parts, being in this soft 
condition, stick together perfectly. There are other ways 
of making wrought iron from cast iron, and wrought iron 
is sometimes made directly from some ores, but the one 
I describe was the first, and is now much practiced. It 
has taken so long to tell about cast and wrought iron, 
that we must let steel go over to another month. Let us 
sum up. Cast and wrought iron really differ in this: 
wrought Iron is nearly pure iron, while cast iron is a com¬ 
pound of iron and carbon. I say nearly pure, because in 
practice it is not found easy to remove every trace of car¬ 
bon, though the amount left is very small, not more than 
one part in four hundred. Cast iron gets its carbon from 
the coal used in reducing it from the ore, and is turned 
into wrought iron by burning out this carbon. Cast iron 
is easy to melt, it will melt in a good hard-coal fire, while 
wrought iron is so difficult to melt, that very few persons 
have ever seen a piece that has been melted. Cast iron 
when hammered does not spread, but breaks off short, 
and shows a shining grained surface ; the wrought spreads 
when hammered, and if heated may he worked into 
almost any desired shape, it is most difficult to break, 
and when broken has a dull, stringy fracture. Cast iron 
is more useful for sonic purposes, becanse it can be melt¬ 
ed and cast into molds, while wrought iron must be work¬ 
ed by hammering, and joined by welding. Cast iron is 
often very hard, and the other much softer, as may be seen 
by filing or drilling the two. Now if you wish something 
to think of, try to count up the uses of iron in these two 
forms—cast and wrought.—or imagine what a world this 
would be, should the supply of iron suddenly cease. We 
think of gold as a very valuable metal, but you will not 
be long in declaring which could be best spared, iron or 
gold. * The Doctor. 
TTSae I>ae«l£Sin«»'s ff'iavst Kxjsci'ience. 
Is there anything more cunning than a duckling? 
One is ever so many times funnier than a little chick, 
which seems to go at business as soon as out of the shell; 
but the duckling seems to be astonished, and looks as if 
it said to itself, “Where am I, and what am I here for ? ” 
Then when the little downy, puffy lump begins to run 
about, how awkward it looks. Such big feet and such a 
broad bill 1 The chick is brighter and livelier until you 
see the two where there is a plenty of water, and then 
the duckling’s ways are the most pleasing. Ducks may 
be brought up from the egg without ever seeing any 
more water than a mere pan or trough for bathing, and 
appear to do well, but they are always seen at their worst 
on land, and at their best in the water, and when they 
are gracefully sailing about they are.much handsomer 
than when waddling along on the ground. They are 
formed for the water, their feet, their shape, and all say 
plainly that they are water birds, and we do not think it 
right to keep them away from it. If you are in doubt, 
just ask the birds, or what is the same thing, show them 
the water, and they will say that they like it by going 
for it. Still ducklings do not like water in every way, 
as the picture shows, and they seem to be very much 
surprised that water coming down upon them is not 
pleasant. They heard the water, and they felt that they 
were made for it, but the water was rather too rough for 
them. Let us hope that their next acquaintance will be 
with smoother water, which they can look down upon, 
and not be obliged to look up at, as the surprised little 
things do in the engraving given above. 
