“Butyl chloride?” Michael frowned.
“It’s known as the ‘death drop’ or the ‘knock-out drop,’ ” said Knebworth, “and it’s a drug very much in favour with sharks who make a business of robbing sailors. A few drops of that in a glass of wine and you’re out!”
Michael took the bottle again. It was a commonplace bottle such as is used for the dispensation of poisons, and in fact the word “Poison” was blown into the glass.
“There is no trace of a label,” he said.
“And really there is no connection with the mysterious car,” admitted the girl. “My surmise is merely guesswork—putting one sinister thing to another.”
“Where was it?”
“In a ditch, which is very deep there and is flooded just now, but the bottle didn’t roll down so far as the water. That is discovery number one. Here is number two.”
From her bag she took a curious-shaped piece of steel, both ends of which had the marks of a break.
“Do you know what that is?” she asked.
“It beats me,” said Jack, and handed the find to Michael.