SCIENCE 
IS 
KNOWLEDGE. 
KNOWLEDGE 
IS 
POWER. 
A PRACTICAL JOURNAL OF 
HOME ARTS 
ToL. VI. 
NEW YORK, FEBEUIKY, 1883. 
No. 2. 
Why and How We are Enabled to Cut 
One Metal with Another. 
BY JOSHUA ROSE. 
OME philosopher 
has said that the 
degree of civilization 
of a people could be 
measured by their 
consumption of iron. 
It is true that as na- 
tions progress they 
increase the employ- 
ment of iron in the 
constructive arts. 
But the age of iron, 
as the era of iron consumption has been 
termed, promises to be succeeded by an 
age of steel, because it is steel that has 
enabled us to cut and shape iron so 
quickly as to enable it to be made and 
formed so cheaply that it could compete 
in price with wood and stone in the con- 
struction of buildings, and with wood in 
the construction of vehicles and other ar- 
ticles where lightness as well as strength 
is a necessity. The steel of which I desire 
more particularly to speak is known b^'^ 
tlie general name of cast-steel, and more 
definitely by the name of tool-steel, since 
it is the special grade or kind of steel from 
which cutting tools are made. But even 
this kind of steel is made in many differ- 
ent grades or kinds, accordhig to the pur- 
pose for which it is to be used. It is suf- 
ficient for our purpose, however, to state 
that the cutting quality of steel is due to 
its being harder than other metals, and to 
the fact that by a simple process it can be 
what is termed hardened, which means 
given an increased degree of liardness. 
This process consists in heating it and 
then suddenly cooling it, and the degree 
of hardness depends upon the degree to 
which it is heated and the suddenness 
Avith which it is cooled after being heated. 
The harder the metal it is to cut the 
more the steel must be hardened. For 
example, if we take a piece of steel and 
cut it into two pieces, and then heat one 
piece red-hot and quench it in water, it 
will cut the soft piece. Suppose, now. 
that we take the hardened piece and 
again heat it to a red heat and then per- 
