Incendiary bombs, filled with highly combustible chemicals such as magnesium, phosphorus or petroleum jelly (napalm), were dropped in clusters to spread fires. The Luftwaffe tended to use thermite incendiaries. They were eighteen inches long and weighed only a couple of pounds. They were dropped in containers of different sizes. The average "breadbasket" was seventy-two incendiaries.
In the later stages of the Second World War they were employed by the Royal Air Force to create firestorms in places such as Dresden. The United States Army Air Force also used them extensively on cities such as Tokyo where there was a large number of buildings made of wood.
For three hours after the night attack got going, I shivered in a sandbag crow's-nest atop a tall building near the Thames. It was one of the many fire-observation posts. There was an old gun barrel mounted above a round table marked off like a compass. A stick of incendiaries bounced off rooftops about three miles away. The observer took a sight on a point where the first one fell, swung his gun-sight along the line of bombs, and took another reading at the end of the line of fire. Then he picked up his telephone and shouted above the half gale that was blowing up there, "Stick of incendiaries, - between 190 and 220 - about three miles away." Five minutes later a German bomber came boring down the river. We could see his exhaust trail like a pale ribbon stretched straight across the sky. Half a mile downstream there were two eruptions and then a third, close together. The first two looked as though some giant had thrown a huge basket of flaming golden oranges high in the air. The third was just a balloon of fire enclosed in black smoke above the house-tops. The observer didn't bother with his gun-sight and indicator for that one. Just reached for his night glasses, took one quick look, picked up his telephone, and said, "Two high explosives and one oil bomb," and named the street where they had fallen.
There was a small fire going off to our left. Suddenly sparks showered up from it as though someone had punched the middle of a huge camp-fire with a tree trunk. Again the gun sight swung around, the bearing was read, and the report went down the telephone lines: "There is something in high explosives on that fire at 59."
There was peace and quite inside for twenty minutes. Then a shower of incendiaries came down far in the distance. They didn't fall in a line. It looked like flashes from an electric train on a wet night, only the engineer was drunk and driving his train in circles through the streets. One sight at the middle of the flashes and our observer reported laconically, "Breadbasket at 90 - covers a couple of miles." Half an hour later a string of fire bombs fell right beside the Thames. Their white glare was reflected in the black, lazy water near the banks and faded out in midstream where the moon cut a golden swathe broken only by the arches of famous bridges.
We could see little men shovelling those fire bombs into the river. One burned for a few minutes like a beacon right in the middle of a bridge. Finally those white flames all went out. No one bothers about the white light, it's only when it turns yellow that a real fire has started.
I must have seen well over a hundred fire bombs come down and only three small fires were started. The incendiaries aren't so bad if there is someone there to deal with them, but those oil bombs present more difficulties.
As I watched those white fires flame up and die down, watched the yellow blazes grow dull and disappear, I thought, what a puny effort is this to bum a great city.
We had an Anderson shelter in the garden. You were supposed to go into the shelter every night. I used to take my knitting. I used to knit all night. I was too frightened to go to sleep. You got into the habit of not sleeping. I've never slept properly since. It was just a bunk bed. I did not bother to get undressed. It was cold and damp in the shelter. I was all on my own because my husband was in the army.
You would go nights and nights and nothing happened. On one occasion when my husband was on leave, I think it was a weekend, we decided we would spend the night in bed instead of in the shelter. I heard the noise and woke up and I would see the sky. They had dropped a basket of incendiary bombs and we had got the lot. Luckily not one went off. Next morning the bombs were standing up in the garden as if they had grown in the night.
On May 10 the enemy returned to London with incendiary bombs. He lit more than two thousand fires, and, by the smashing of nearly a hundred and fifty water mains, coupled with the low tide in the Thames, he stopped us putting them out. At six o'clock next morning hundreds were reported as out of control, and four were still glowing on the night of the l3th. It was the most destructive attack of the whole night Blitz. Five docks and seventy-one key points, half of which were factories, had been hit. All but one of the main railway stations were blocked for weeks, and the through routes were not fully opened till early June. Over three thousand people were killed or injured. In other respects also it was historic. It destroyed the House of Commons.