The Last Drop of Water (1911)

Synopsis (complete with spoilers): A woman has two suitors; one is shy and the other is overly imposing. The woman ends up marrying the latter, who turns out to be a drunkard. Then the three of them are in a caravan heading west. They are attacked by Natives. They run out of water. The two men volunteer to go get more of it. The shy one is passing out due to thirst, but is saved by the other one, who offers him what is left of his supply of water and shortly dies. The cavalry arrives and saves the caravan.