1.   The cold autumn-night air had chilled her to the bone, numbing her limbs with the dampness of the ground.

2.   At night, when cool air chills the helium, the gas contracts and loses lift.

3.   Air chilled along the slopes of the Sierra at night drains into the surrounding valleys where Benton lies.

4.   Air will chill.

5.   But at night the cool air chills the balloon gas, reducing its lift and forcing the balloon to descend.

6.   Fog rolled in and the night air chilled.

7.   The air will chill.

8.   The air chilled.