No one was allowed even to go in the field unless equipped with a gas-mask.
His gas-mask had been blown to atoms with Observation-Post Fourteen.
With a gas-mask on a man is not more than fifty per cent efficient.
Under the mesh of his gas-mask the lean lines of his jaw went taut.
"God, I envy a man who can snore through a gas-mask," said Randolph.
A member of her crew, in a gas-mask, stepped out of the port doorway.
It takes about twenty seconds to put on a gas-mask properly.
They wore the same uniform as himself and when he took the gas-mask off of one of them the man's face was strangely peaceful.
"And don't forget your helmet and gas-mask," he called, as I stepped from the car into a foot of oozy mire.
He examined his gas-mask from force of habit before stepping out into the fog once more, then contemptuously threw it aside.