He had to assume exclusive use, such as employed by Tosdal and Triesting. It wasn't certain, but possible.
By the end of the week, by driving and looking, he cut the list down to twenty-seven. In two days more there were only eleven left on the list. He knocked seven more off in the two days of closer observation.
Which left four companies starting with T who used Higgenson Rapid Transit. Others he had seen using Higgenson, but all the others had at least one other truck from a rival company taking out deliveries. These four were the exclusives.
Thornton Manufacturing. Temple City Products. Top-Notch Corporation. Thompson Electric. Four where there should have been five.
It wasn't hard to get hold of catalogues and bulletins from the firms. He hesitated to approach them directly, and finally did his shopping through retail outlets. In a week he had four more parts to his assembly. And each one was as he had known it must be.
There was still one part missing. He could make it himself, he knew, but Tredel preferred to find out where it came from, to have a part that was actually made to go on the assembly.
Back to the classified index, back to his driving. And three weeks later he still had only the six parts.
In the fourth week he found the seventh part. Under his own nose again. In his own factory. In an intercommunication unit he had designed himself.
Only it wasn't quite the way he had designed it, before the war. There were several changes. Basically it was the same unit, but the changes had been made to conform and allow the use of a new part.
Morton! Tredel had to think, then. Really think. That wasn't possible. Or was it? How much did he know about the man, really? Outside of the fact that they'd been friends for a long time, now, and Morton had proven himself trustworthy enough—or had he? How much did you ever know, really, about a friend, or anyone besides yourself? Even yourself?
He couldn't go to Morton. No, he couldn't go to Morton whether the man was innocent or guilty.
Still, he found out what he wanted to know.
They'd had a large order for intercom units during the war. The customer had the recpiired priority to make materials and assembly time available. He'd insisted on a couple of changes, which had been made. It called for several new parts, which, since they didn't have the facilities, they'd subcontracted to Young Brothers. They'd switched the whole design, then, thinking it simpler to make all the intercoms the same, and there was little cost difference.
The customer was still on the books, still taking intercoms and spares. Tredel wasn't surprised to find that the spares on his suspect
