Explosives

Introduction

Explosives are used to crumble large amounts of solid materials into removable sizes.   Explosives are important in mining and excavations for buildings, tunnels, waterways, and railroads.   The innovations in explosives resulted in greater blasting power and safety.

To 1790

The only explosive available in early America, known from antiquity, was gunpowder, which is a mixture of potassium nitrate (saltpeter) or sodium nitrate, charcoal and sulfur in various proportions, depending on use.   The ratio 75:15:10 is common.

1790-1799

1800-1809

1810-1819

1820-1829

1830-1839

1840-1849

In 1845, the German chemist, Friedrich Schönbein, accidentally discovered that a mixture of nitric and sulphuric acids acting on purefied cotton or wood pulp produced an explosion.   The exposives was called nitrocellulose or guncotton.   However, nitrocellulose was too unstable and dangerous to have practical applications.

In 1847, the Italian chemist, Ascanio Sobrero, combined the acid mixture with glycerine to produce what became known as nitroglycerine, C₃H₅N₃O₉.   It decomposes with explosive force when heated or jarred, so it is dangerous to make and handle.   Sobrero himself suffered a sobering explosion and did no further work with it.   Although this explosive eventually was used in weapons to kill and maim, it also improved the productivity of mining and quarrying because it had more explosive power than the traditional gunpowder, which had been used for centuries. ^{Asimov 357}

1850-1859

1860-1869

Trinitrotoluene - TNT - CH₃C₆H₂(NO₂)₃ , is a powerful explosive, but relatively insensitive to heat and jarring, so it is safer than other high explosives.   A detonator is used to set it off.   TNT is used as one ingredient in a variety of explosive mixtures made for ammunition because it melts at a low temperature (81°C) and can be poured into molds for shells.   It also is used in excavations.   TNT was synthesized for the first time by Alfred Nobel in 1863.

Dynamite is nitroglycerine mixed with inert, porous materials, such as wood pulp or sawdust to make an explosive that is less volatile.   It was invented by the Swedish scientist, Alfred Nobel, in 1866, and soon replaced gunpowder and nitroglycerine as the explosive for blasting rock during excavations.   Dynamite usually is set off by a small explosive, called a detonator, such as fulminate of mercury.

1870-1879

1880-1889

1890-1899

1900-1909

1910-1919

1920-1929

1930-1939

1940-1949

1950-1959

1960-1969

1970-1979

1980-1989

1990-1999