ulled the trigger of
his gun. The bullet hit something which was solid heavy metal,
ricocheted, ricocheted again and the second hood howled and leaped
wildly into the air. He came down in the flowing flood of spilled
detergent, flat on his stomach, and with marked forward momentum. He
slid. The floor of the plant had recently been oiled to keep down dust.
The coefficient of friction of a really good detergent on top of
floor-oil is remarkably low,--somewhere around point oh-oh-nine. Hood
number two slid magnificently on his belly on the superb lubrication
afforded by detergent on top of floor-oil.

The first hood staggered. Something else fell from the shelf. It was a
carton of electric-light bulbs. Despite the protecting carton, they went
off with crackings like gunfire. Technically, they did not explode but
implode, but the hood with the revolver did not notice the difference.
He leaped--and also landed in the middle of the wide streak of
detergent-over-oil which might have been arranged to receive him.

He remained erect, but he slid slowly along that shining path. His
relatively low speed was not his fault, because he went through all the
motions of frenzied flight. His legs twinkled as he ran. But his feet
slid backward. He moved with a sort of dignified celerity, running fast
enough for ten times the speed, upon a surface which had a frictional
coefficient far below that of the smoothest possible ice.

Detective Sergeant Fitzgerald gaped, his mouth dropped open and his gun
held laxly in a practically nerveless hand.

The thing developed splendidly. The prone gunman slid out of the wide
double door, pushing a bow-wave of detergent before him. He slid across
the cement just outside, into the open garage whose delivery-truck was
absent, and slammed with a sort of deliberate violence into a stack of
four cardboard drums of that bone-black which is used to filter
cleaning-fluid so it can be used over again in the dry-cleaning machine.
The garage was used for storage as well as shelter for the
establishment's truck.

The four drums were not accurately piled. They were three and a half
feet high and two feet in diameter. They toppled sedately, falling with
a fine precision upon the now hatless, running, sliding hood. One of
them burst upon him. A second burst upon the prone man--who had butted
through the cardboard of the bottom one on his arrival. There was a
dense black cloud which filled all the interior of the g