In the village, the local pub is called 'The White Hart'. With the Science Fiction story, i.e., aliens, this is an obvious nod to SF author Arthur C Clarke, who wrote a collection of short stories entitled "Tales from the 'White Hart'.
The first portable electric light (flashlight) was powered by large batteries called dry cells. They were relatively heavy. And were invented in the late 1890's.
Hart is an archaic term for a deer.