Their boilers are atomically fired. They use atoms, which are minute particles of elemental matter, in some way, combined into something called a pile. These piles produce heat — more heat than the vampire machines can effectively use. They radiate it into the air. The machines burn to touch. The places they frequent are dead places. Men who open and examine piles invariably sicken and die, poisoned by some agent or residue left by the vampire machines to prevent such exploration. This avenue of inquiry is entirely blocked to us. All that we know are the words passed down — atoms and piles — and these tantalize and taunt from beneath a crushing weight of ignorance.
* * *
The vampire machines cannot function without liquid to boil. This is their single weakness. It is why we live in the desert.
There are friendlier places and we know them well. Green valleys and rolling, forested hills. The rivers and lakes that feed this growth provide succor to our murderers.
Our village is one of the most prosperous in the central valley. It has a high wall, and we mount watchmen in all weather. There is a clear view in every direction and no intruder — man or machine — can approach unseen. We have an ample supply of water from our qanat, and our Parceller sees that it is shared fairly among all the households. Our village is rich from tin, which we mine in channels adjacent to and interconnected with our qanat.
The qanat is a sort of horizontal well, bringing water from the eastern mountains to our village. We keep it clear of debris and animals in cooperation with villages up-stream. Its entire course runs below ground. We cannot keep the vampire machines out of the qanat, but it does not serve them — the flow is too weak for their needs. There are also gates and traps to hinder and ruin them.
Some of the machines seek us out, even in the deep desert, and these have no fluid save our blood to fill their boilers. In their thirst they destroy entire villages. Sometimes we find them, lifeless, crusted blood choking their exhausts, the steam having deserted them at last. Even machines can miscalculate.