All 3 Uses

although
in
Brave New World
(Edited)

Although falling short of the length of the Mississippi-Missouri, the Nile is at the head of all rivers as regards the length of its basin, which extends through 35 degrees of latitude …
p. 25.7

although = even though (used to connect contrasting ideas)
The words come rushing out. "Although — falling — short — of …"
p. 26.1
...the social body persists although the component cells may change.
p. 97.4 *

Definitions:

(1) (although)
even though -- used to introduce an idea that contrasts with or makes the main statement surprising

At the start of a sentence, although can play a role similar to words like however, yet, still, even so, on the other hand, or nonetheless—all of which signal contrast. In the middle of a sentence, although can sometimes be used where but or though might also work, but though or but often sound more natural. For example, "She's a great teacher, though not the most popular" is usually smoother than "She's a great teacher, although not the most popular."
(2) (meaning too rare to warrant focus)