glean

glean \GLEEN\, verb:

1. To learn, discover, or find out, usually little by little or slowly.
2. To gather (grain or the like) after the reapers or regular gatherers.
3. To gather slowly and laboriously, bit by bit.

From what little I can glean, it's the edited journal of a voyage from Sydney to California by a notary of San Francisco named Adam Ewing.
-- David Mitchell, Cloud Atlas: a Novel

We all looked at each other, trying to glean something each from the other.
-- Bram Stoker, Dracula

Glean traces its origin back through Latin to the Celtic glan, "clean, pure." The sense "to learn or gather slowly" appears in English before the sense of "to gather grain left by the reapers."