The only factor that could possibly have astonished him, just now, would have been the nonappearance of that slight, luminous cloudlet at the precise spot and moment designated.
Neither Bohannan, Alden, nor Rrisa was watching the slow descent of the lethal gas.

All three had their eyes fixed on their own lethal-gas pistols and on their watches.

At mathematically the correct second, Bohannan discharged his piece, correctly sighting direction and elevation.
As he pressed trigger, a light sighing eased itself from the slim barrel.

Something flicked through the leaves; and, almost on the instant, the phenomenon of the little phosphorescent spot repeated itself, though in a different place from the first one.

Captain Alden's and Rrisa's shots produced still other blurs of virescence.
Then, as they all waited, crouching, came another and another tiny explosion, high aloft, at precisely ten-second intervals.