“Why, you saw what I got out of it: arithmetical errors which proved conclusively that he was a careless worker who didn't take any trouble at all to verify his results.”
“I had a kind of notion that you got more out of it than that, sir, or you wouldn't have asked to see Markfield's notebook as well. It doesn't take someone else's notebook to spot slips in a man's arithmetic, surely.”
Sir Clinton gazed blandly at his subordinate:
“Now that you've got that length, it would be a pity to spoil your pleasure in the rest of the inference. Just think it out and tell me the result, to see if we both reach the same conclusion independently. You'll find a weights-and-measures conversion table useful.”
“Conversion table, sir?” asked the Inspector, evidently quite at sea.
“Yes. ‘One metre equals 39·37 inches,’ and all that sort of thing. The sort of stuff one used at school, you know.”
“Too deep for me, sir,” the Inspector acknowledged ruefully. “You'll need to tell me the answer. And that reminds me, what made you ask whether the dose could have been fifteen times the maximum?”
The Chief Constable was just about to take pity on his subordinate when the desk-telephone rang sharply. Sir Clinton picked up the receiver.
“. . . Yes. Inspector Flamborough is here.”
He handed the receiver across to the Inspector, who conducted a disjointed conversation with the person at the other end of the wire. At length Flamborough put down the instrument and turned to Sir Clinton with an expression of satisfaction on his face.