The black powder is produced with using saltpeter, and that saltpeter is a reason for smoke to appear in barrel after discharging projectile. Nowadays the black powder is produced like grain-likes and those grains are of irregular shape.
There are some characteristics that determine a knife or other stuff like the cold steel. First of all it is important for blade of knife to be no less than 90mm. The thickness of blade has to be no less than 2,5mm.
Firearm is a weapon, especially a portable gun or pistol, from which a projectile can be discharged by an explosion caused by igniting gunpowder, etc. There are two kinds of powder that is used for discharging of projectile. It can be the black powder or smokeless powder. An invention of firearms had started the era of artillery. Before the invention of firearms there were only cold steel and that weapon were used for waging a war against someone. Though, appearance of firearms made wars more destructive and dangerous.
In case when projectile is discharged with the help of smokeless powder, there is no smoke in the barrel. The smokeless powder may be of three kinds: cordite, bullistide and common white powder. No matter on the type of smokeless powder it has the same action and conditions no smoke unlike the black powder. The reason for no smoke after discharging using the smokeless powder is the ingredients of this powder. Those ingredients are gasiform and so they produce no smoke.
The black powder is produced with using saltpeter, and that saltpeter is a reason for smoke to appear in barrel after discharging projectile. Nowadays the black powder is produced like grain-likes and those grains are of irregular shape. The nitre is an oxidizer in the black powder and the main combustible component is coal. The brimstone is also used for producing black powder. Brimstone makes powder harder and promotes its combustibility. It won't take many efforts to combust the black powder, so it is rather dangerous. The temperature of powder's flash is about 300 C.
As for the cold steel it was used for combats long ago before the firearms appeared. It is a weapon one can not use for remote fight. It is a kind of weapon one may use only during the close-in fight. Though, the times came when firearms appeared the culture of cold steel hasn't disappeared. It is okay to say "the culture" as using cold steel in combat is a real culture. There are certain rules about how one has to hold his knife or sword and so on and so forth. This kind of weapon is not as destructive as the firearms, though it is not less dangerous. Moreover, there is a variety of cold steel to use during different combats.