Development and use in World War I
The first incendiary devices to be dropped during World War I fell on coastal towns in the south west of England on the night of 18–19 January 1915. The small number of
German bombs, also known as firebombs, were finned containers filled with
kerosene and oil and wrapped with tar-covered rope. They were dropped from
airships. On 8 September 1915, Zeppelin L-13 dropped a large number of firebombs, but even then the results were poor and they were generally ineffective in terms of the damage inflicted. They did, however, have a considerable effect on the morale of the civilian population of the United Kingdom.
After further experiments with 5-litre barrels of
benzol, in 1918, the B-1E
Elektron fire bomb (German: Elektronbrandbombe) was developed by scientists and engineers at the
Griesheim-Elektron chemical works. The bomb was ignited by a
thermite charge, but the main incendiary effect was from the
magnesium and aluminium alloy casing, which ignited at 650° Celsius, burned at 1,100 °C and emitted vapor that burned at 1,800 °C. A further advantage of the alloy casing was its lightness, being a quarter of the density of steel, which meant that each bomber could carry a considerable number.
German High Command devised an operation called "The Fire Plan" (German: Der Feuerplan), which involved the use of the whole German heavy bomber fleet, flying in waves over London and Paris and dropping all the incendiary bombs that they could carry, until they were either all shot down or the crews were too exhausted to fly. The hope was that the two capitals would be engulfed in an inextinguishable blaze, causing the Allies to sue for peace.
 Thousands of Elektron bombs were stockpiled at forward bomber bases and the operation was scheduled for August and again in early September 1918, but on both occasions, the order to take off was countermanded at the last moment, perhaps because of the fear of Allied reprisals against German cities.
Royal Air Force had already used their own "Baby" Incendiary Bomb (BIB) which also contained a thermite charge.
 A plan to fire bomb New York with new long range Zeppelins of the L70 class was proposed by the naval airship fleet commander
Peter Strasser in July 1918, but it was vetoed by Admiral