Both Uses of

descend

in

To Kill a Mockingbird

At first we saw nothing but a kudzu-covered front porch, but a closer inspection revealed an arc of water descending from the leaves and splashing in the yellow circle of the street light, some ten feet from source to earth, it seemed to us.
p. 57.3 *

descending = moving downward

The remainder of the afternoon went by in the gentle gloom that descends when relatives appear, but was dispelled when we heard a car turn in the driveway.
p. 145.9 *

descends = arrives

Definitions:

(1) (descend as in: descend the mountain)
move or slope downward
(2) (descend as in: in descending order)
move down a scale -- as from larger numbers to smaller, or higher notes to lower
(3) (descend as in: descend from royalty)
figuratively, to have come down a path from the past; i.e., to originate or come from -- such as in reference to ancestors or evolutionary origins
(4) (descend as in: descend into poverty)
figuratively, to move downward to a worse or less prestigious situation
(5) (descend as in: descend into deeper thought)
to move from a higher level of abstraction downward to a lower one (from more general to more specific); or to move from superficial to deeper thought
(6) (descend as in: thieves descended upon us)
to come or arrive -- especially suddenly or from above or as an attack