A manganese steel of 11 to 14 per cent. is too hard to be machined.  It has to be cast or ground into shape and is used for burglar-proof safes and armor plate.  Chrome steel is also hard and tough and finds use in files, ball bearings and projectiles.  Titanium, which the iron-maker used to regard as his implacable enemy, has been drafted into service as a deoxidizer, increasing the strength and elasticity of the steel.  It is reported from France that the addition of three-tenths of 1 per cent. of zirconium to nickel steel has made it more resistant to the German perforating bullets than any steel hitherto known.  The new “stainless” cutlery contains 12 to 14 per cent. of chromium.

With the introduction of harder steels came the need of tougher tools to work them.  Now the virtue of a good tool steel is the same as of a good man.  It must be able to get hot without losing its temper.  Steel of the old-fashioned sort, as everybody knows, gets its temper by being heated to redness and suddenly cooled by quenching or plunging it into water or oil.  But when the point gets heated up again, as it does by friction in a lathe, it softens and loses its cutting edge.  So the necessity of keeping the tool cool limited the speed of the machine.

But about 1868 a Sheffield metallurgist, Robert F. Mushet, found that a piece of steel he was working with did not require quenching to harden it.  He had it analyzed to discover the meaning of this peculiarity and learned that it contained tungsten, a rare metal unrecognized in the metallurgy of that day.  Further investigation showed that steel to which tungsten and manganese or chromium had been added was tougher and retained its temper at high temperature better than ordinary carbon steel.  Tools made from it could be worked up to a white heat without losing their cutting power.  The new tools of this type invented by “Efficiency” Taylor at the Bethlehem Steel Works in the nineties have revolutionized shop practice the world over.  A tool of the old sort could not cut at a rate faster than thirty feet a minute without overheating, but the new tungsten tools will plow through steel ten times as fast and can cut away a ton of the material in an hour.  By means of these high-speed tools the United States was able to turn out five times the munitions that it could otherwise have done in the same time.  On the other hand, if Germany alone had possessed the secret of the modern steels no power could have withstood her.  A slight superiority in metallurgy has been the deciding factor in many a battle.  Those of my readers who have had the advantages of Sunday school training will recall the case described in I Samuel 13:19-22.