The ship is walked out of the shed to the mooring mast, with the shine still attached. The tendrils are waving about as before, not particularly reaching out to touch anyone or anything.

Gertrude spots Squadron Leader Rope and Colonel Richmond among the people going on this flight. They go aboard up the mast, and the ship drops lines, backs away and sets off. The halo of good luck follows it; it’s not precisely conformal to the envelope, but trails slightly, a bit like the flame from a match being moved through the air. The ship rapidly moves out of sight, with a brief oil spray from one of the engines.

Audrey and Lin Tan take the opportunity to sneak into the drafting office, where Audrey looks through the files and sees that the odd girder arrangement was present on the drawings well before construction started, and it’s been signed off by Rope; she then gets distracted by aeronautical design details, and Lin Tan pulls her out. Some file references lead them to Rope’s office, where his correspondence with J D North of Boulton & Paul is stored (clearly not having been looked at lately); it definitely seems to be Rope’s idea, as North raised a query about it, and Rope insisted (showing him stress calculations).

Meanwhile, Gertrude and Millie have talked their way into the empty shed, to take a look at the layout with the thought of improving crane arrangements for lifting fabric panels. Gertrude has an idea about using panels of fabric around the transverse frames to prevent gas-bag rubbing, working a counter-pattern into the construction to defuse the luck separation; but this would take a lot of fabric, adding a fair bit of weight, and in any case there’s not enough of the stuff in stock.

Audrey and Lin Tan travel to London to try to get in touch with Ramsey; there’s no immediate response to a message left at the dead drop, so they call him, and he meets them. They’re seeking directions, and he explains that what his political masters would ideally like is a failure of the ship that is directly attributable to its specific design (thus not causing damage to the rest of the programme); but for himself, he’s concerned to prevent the loss of life. Previous experience with the Office’s means of divination suggest that acting to prevent its forecasts does not seem to be resisted. The two start to consider ways of making the gas bags wear out and leak.

Meanwhile, Gertrude and Millie have been considering other means of sabotage. Millie gets through to St John again, and he’s had some success with shaving down the spokes on his models; doing this carefully seems to reduce the power of the luck separation effect, so that it can’t maintain quite as much of a potential difference.

The airship returns a little before midnight, and is moored and brought into the shed. There’s muttering about an oil cooler that prevented them from doing the full-speed tests they’d hoped for, but things are still on track for the departure to India on Friday night.