1.   Its floor is covered with a fine layer of chalk dust from the calloused palms of legions of lifters.

2.   Now those slight differences of electrical potential had disappeared, like the chalk dust at the end of the lesson.

3.   There were the eternal school smells of chalk dust, wax crayons, cedar shavings, damp wool, and warm children.

4.   He wiped the chalk dust off his hands.

5.   He looked down at his fingers and noted the chalk dust on their tips.

6.   And when the chalk dust settled, history was made last night.

7.   A morning smell of coffee and stale beer and chalk dust pervaded the room.

8.   He drew chuckles as he wiped the board clean and got sprayed with a little chalk dust just like an ordinary professor.