Free With My Little Eye by Gerald Hammond

replacing oxygen. We breathe it out all the time and plants breathe it in. That’s about the lot.’
    â€˜A lot of it goes into fizzy drinks,’ Tash said. ‘It’s produced naturally in huge quantities. It’s used in firefighting and refrigeration. They use it for artificial smoke or fog in the theatre. Sometimes it’s used as the inert gas in welding processes and also for hardening the casting moulds for metals.’ She was hiding a trace of a complacent smile.
    Such a rush of erudition was unprecedented. There was a stunned silence. The detective chief inspector broke it with an effort. ‘How do you know all this?’
    She tapped the laptop. ‘I’ve just Googled it. Sometimes carbon dioxide is used in greenhouses because carbon dioxide from the air is where plants get most of the carbon for growing, not from fertilizers in the ground. The oxygen part gets returned to the atmosphere. But that particular process is reversed slightly at night, which is why they take flowers out of a sickroom at night.’
    The detective chief inspector made an irritated sound. ‘And the deceased was a gardener! It’s used as the inert gas in welding and Mr McLeish has a garage and workshop. And I suppose the university uses it?’
    â€˜I would think so,’ Douglas said. ‘They have an anechoic chamber for noise experiments and anechoic chambers are lined with foam plastic which is very flammable. I would expect there to be a system for flooding the chamber with carbon dioxide whenever the smoke detectors are triggered. I did some work for the other university,’ he explained. ‘It must also be used a lot in both teaching and research, but you’d better ask the professor about that. Or Mr Campion, his technician friend.’
    â€˜I see. And does anybody here go in for amateur theatricals?’
    â€˜I’ll save Tash the distress of having to be a telltale,’ said Douglas. ‘The two ladies do. I suspect that that’s a major factor in their care for their figures. Their club is putting on
Oklahoma
in the autumn, I believe.’
    The detective chief inspector sat back and closed his eyes for a minute. Douglas could almost believe that he was blinking back a tear. ‘That’s great!’ he said. ‘Oh, that’s just dandy! To look at it from the other end, is there anybody around here who couldn’t beg, borrow or steal a cylinder of carbon dioxide?’
    â€˜If you’re going to start from the other end,’ Douglas said, ‘you’d better get on to the suppliers and find out who they’ve supplied it to.’
    That was too much. ‘Thank you for your helpful suggestion,’ said DCI Laird through gritted teeth. ‘I would never have thought of that for myself,’ He got to his feet and stalked out of the room.
    â€˜Ouch!’ Douglas said. ‘I should have remembered how insulting it is to be told to do what you were going to do anyway. You’d better type up your notes and we’ll give them to him quickly as a peace offering.’
    â€˜All of them?’
    â€˜Stop after the mention of
Oklahoma!
’
    Tash looked at her notes. ‘I see what you mean.’

TWELVE
    D ouglas’s major client had a job for him. It had lain fallow for months and then, when the client had at last made up its many minds, the job had been deemed urgent. He and Natasha took an early breakfast and escaped the clutches of their curious neighbours only to be bearded at the car door by a newspaper reporter. The media, it seemed, knew only that a man had been found dead. Under pressure by a practised interrogator to reveal who had found the body, Douglas had at length admitted that he had been present when the body was found.
    â€˜But I did not see anything to explain the death,’ he said with truthfulness, ‘so bugger off. And you can quote me on that.’
    â€˜That goes for me too,’ said