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•Three Greatest Natural Discoveries that Drive Businesses 147

black powder covered in textiles such as jute yarn. The cord is covered with water-
proof material such as asphalt and finished off with a layer of textile, or nowadays
plastic.

Black powder is now illegal for use in mines in most countries and its use is
declining rapidly. However, it still has no substitute for certain military purposes,
and nothing equal to it has been found for making a safety fuse.

Ascanio Sobrero made the next big step forward when he discovered nitro-
glycerine or blasting oil. This compound was so unstable and its detonation so un-
reliable that it remained more or less in the laboratory until the work of Immanuel
Nobel and his son Alfred. They built plant for the manufacture of nitro-glycerine in
Sweden and the USA. However, most experts believe that Nobel’s invention of the
blasting cap, a device for detonating explosives, was the next major step forward
from black powder. Certainly the cap which Nobel created was still in use more
than 50 years later.

There still remained the problem of the instability of nitro-glycerine until Nobel’s
second most important discovery. He found that by mixing pure nitro-glycerine
with other substances, eventually known as dopes, he could render the nitro-glycer-
ine stable and much easier to work with. Indeed he could vary the ratio of nitro-
glycerine to dopes to produce an explosive that was not only more efficient but
produced different strengths of explosion.

The military requirement for explosives has some differences to civil uses. They
need to be insensitive to shock and friction and unlikely to be easily detonated with,
for example, small-arms fire. They often have to withstand long periods of adverse
storage without deteriorating, and must be fired in projectiles or dropped in aerial
time bombs without premature explosion. Many types have hideously complicated,
not to say devious, fuses for detonation.

These requirements are met in the main by trinitrotoluene or TNT. Indeed
non-nuclear warheads still contain it as part of their chemical content, although
there are some other specialist explosives in use.