“Gee! I’m beginning to get you! Yes, they’re all made standard. There are several models, you understand, but all the magnetos of any given model are interchangeable.”
“Good! Now tell me, what’s to prevent my man from buying a duplicate magneto, damaging the armature winding invisibly with a needle, and running it on his car till it gives up; then taking it off, carrying it as a spare, and putting it on again when he had got the car to the point of breakdown?”
“You’ve got it, Mr. French! Great, that is! I didn’t think it was possible, and there, as you say, it’s as simple as A B C.”
“Well,” said French. “Then did he?”
Illingworth looked his question and French went on:
“I’m looking to you for proof of the theory. First, do these magnetos carry a number? If so, is there a record of the number fitted to each car? If so, what was the number supplied with Mr. Berlyn’s car? Next, is that the number that came in for repair? Next, was there a magneto of that type ordered separately recently, and if so, by whom?”
“Steady on, Mr. French,” Mr. Illingworth laughed. “What do you take me for? I’m not a detective. Now let’s go over that again, one thing at a time. Magnetos carry a number, yes, and we have a note of the numbers supplied to the different car manufacturers. They can tell you the number of the magneto they put on any given car. What car are you interested in?”
“A fifteen-twenty four-seater Mercury touring car, number thirty-seven thousand and sixteen, supplied through Makepeace to a Mr. Berlyn of Ashburton.”
“Right. I’ll ring up the Mercury people now.”
Mr. Illingworth was indefatigable in his enquiries, but he was not prepared for the state of delighted enthusiasm into which his results threw French.