"Victory had been snatched from the very jaws of defeat."  This line comes after the peons on the plantation of Leiningen have begun their deadly march.  Refusing to leave his plantation to the ants's ravaging, Leiningen devises strategies of defense.  When Leiningen took over this "model farm and plantation," he says, he prepared it for anything and everything.  So, his water-filled ditches are one of the defenses that Leiningen employs against the onslaught of millions of ants.  He opens the dam, which fills these ditches, making "an imposing girdle of water completely around the plantation.  This twelve-foot water ditch seems to afford all the security necessary as the people and creatures remain on the other side. 

As a further security, Leiningen has an inner ditch built that is smaller than the other.   This ditch extends around the perimeter of all the buildings.   Into this concrete ditch, filled with concrete, Leiningen has inflow pipes from three great gasoline tanks. If by some miracle the ants pass over the other ditch, the gasoline wall will prevent them.

Thousands of millions "of voracious jaws bearing down" upon the men appears, but they are deterred by their "failure to find a way over the ditch."  However, they begin to climb and march over the dead bodies of other ants, and Leningen must think fast.  Fortunately, the ants did not assalt simultaneously along the entire length of the ditch, or the outlook for the defenders "would have been black indeed."  But, Leiningen puts the gasoline into action.  Responding, the ants come along a widening line.  But, as the ants climb onto the men's arms, Leiningen shouts to them to douse their arms in the gasoline.  As the water rises that moves more swiftly "carrying away more and more of it on the hastening current.

As the water washes the ants away,  Stephenson writes, Victory had been snatched from the very jaws of defeat." But, the ants use leaves to pass across the water as on rafts.

At what point in the story does it first seem that leiningen has snatched victory “from the very jaws of defeat”? How do the ants recover?

The famous short story "Leiningen Versus the Ants" by Carl Stephenson tells of a plantation owner in Brazil who refuses to leave his land in the face of a formidable invasion of deadly ants. Instead, he decides to stay and fight them with the help of some of his employees.

Leiningen constructs a water-filled ditch or moat around his plantation, and he has his workers lop off the branches of trees overhanging the moat. He figures then that the ants would have to construct rafts to get across and supposes that his plantation is safe. He constructs another inner moat of concrete that he plans to fill with petrol and set on fire if the ants manage to get past the water moat.

The ants are temporarily stopped by the water in the ditch, but then they begin to pour into it in huge masses, walking over the bodies of the drowning ants. They also roll down the bank into the water in massed clumps. Leiningen sends someone to dam the river more strongly so that the water level in the moat will rise and the water will flow more swiftly. This causes the mass of ants to disperse. This is when it seems that "victory had been snatched from the very jaws of defeat."

Only a few ants make it across, and the rest recover by temporarily retreating. The ants then construct rafts of leaves and float across the water. They are temporarily repelled, but eventually make it all the way across.

Leiningen signals a retreat to the inner circle beyond the smaller concrete moat. He fills the moat with petrol, and when the ants attempt to cross, he lights it. He does this again and again until the petrol is almost gone. Then he is forced to make a run for the dam while the ants attack him, and he lets loose the dammed river upon the plantation, flooding it but at the same time destroying the ants.

In "Leiningen and the Ants," at what point in the story does it first seem that Leiningen has snatched victory "from the very jaws of defeat " ?

In this Man vs. Nature story, a determined owner of a coffee plantation is convinced that he can prevent a plague of ants from devastating all that he has worked so hard for on his settlement. Around three sides of his plantation, Leiningen has had a ditch made as a defense against ants. The ends of this "horseshoe" run into the river, and at the end near the house and the outbuildings, there is a dam by means of which the river's water can be diverted into the ditch. In addition, Leiningen has a concreted "inner moat" constructed; into this moat, Leiningen has petrol piped in as a further deterrent for the ants, making "an impassable protection for the besieged and their dwellings and stock."

When the army of ants marches upon the plantation, "shoals of ants" are carried away by the current into the middle why they drown. But, others use the dead bodies as stepping stones. So, a peon is sent to the weir to dam the river and thus increase the speed and power of the water entering the ditch. Before this can happen, however, the ants get across the ditch. Nevertheless, the stronger damming of the river begins to have an effect. 

Visibly the swiftness and power of the masses of water increased, swirling into quicker and quicker movement its living black surface, dispersing its pattern, carrying away more and more of it on the hastening current.

It is then that "[V]ictory had been snatched from the very jaws of defeat."