'Why, for the moment I thought you was a ghost. Can't be more than an hour and a half since you left for Scotland.'

'Scotland?'

'Yes, Sir. You came here round half past two. Special order, you said. Needed urgent for our place in the 'Ebrides. I got hold of Tommy Carden and we loaded twenty drums out of the store on to a runabout. He drove you with it out to the airstrip and when he got back he told me you meant to deliver it yourself and had gone off with it in a plane. Leastways, that's what I thought he said.'

Verney, Khune and Barney stared at the man dumbfounded. The same awful thought was in all their minds. Lothar had never intended to keep the appointment on Lone Tree Hill. He had made it only to get Otto out of the Station for the afternoon. He had arrived there in an aeroplane and impersonated his brother. He had not got the formula, but he had done far better. He had made off with twenty drums of the fuel all ready for use.

17.Unhappy return

Verney was quick to realize that unless he intervened at once, Otto might say something that would start all sorts of undesirable rumours running round the Station, so he glanced at his watch and said:

'I really think we ought to postpone our visit to your laboratory, Mr. Khune, until after we have been along to the airstrip. Perhaps we'll have time to see it later.'

Khune gave him a blank stare for a moment, then took the hint, muttered something to the doorkeeper about 'change of plans' and turned back to the car. They all got in it and, as soon as the engine was running, he exclaimed:

'It must have been Lothar! How utterly damnable! Yet there's no other explanation.'

'None, I'm afraid,' C.B. agreed grimly. 'I didn't want you to start cross-questioning that chap, because the fewer people to get wind of it that something's wrong, the better. He was quite definite though, and he can hardly have been dreaming. We'll know for certain as soon as we get to the airstrip. Is it usual to send the stuff up to Scotland in an aircraft?'

'Yes. It's not only quicker, but safer, than rail, and if some of it went astray. . . .' Khune broke off short, and ended with a groan.

'It looks as if twenty drums of it has! Is that the normal quantity in a consignment?'

'No. Usually we send eighty to a hundred drums at a time.'