Orlandine sat back and remembered being eight years old and observing a demonstration in a basic chemistry class. The whole lesson had been conducted in a virtuality, but that did not change the fundamental facts. She and her classmates had sat in a representation of a pre-millennial classroom, while the AI in charge apparated as an old gentleman in Victorian garb. Inside a cabinet, whose front door was armour-glass, rested a conventional glass vessel filled with misty gas. Behind this, screwed into the back of the cabinet, was an ancient filament light bulb. The bulb came on with a dull red glow.

‘As you can see,’ the teacher pointed out, ‘no reaction. Red light does not contain sufficient energy to split chlorine molecules. But now, observe.’

While she watched, the chemical formulae had played in her mind, through her early haiman implants, and she understood those formulae just as she understood mathematics, on an almost instinctive level. The light bulb grew brighter, changing to a blue-white glare. Instantly the glass vessel exploded.

‘The photochlorination of methane,’ the teacher explained. ‘The light needs a wavelength of no more than 494nm to split the chlorine molecules into radicals, which can then combine with the methane to form methane radicals and hydrochloric acid. This is an example of a strong, exothermic chain reaction. Now let us look at this in detail . . .’

The classroom faded and, from a vantage in albescent space, the pupils observed a nanoscope view of the actual molecules and their reaction. As Orlandine recollected, the lesson then moved on to the quantum processes involved—basic chemistry for haiman children had been rather more advanced than for others.

Photochlorination.

She needed to destroy the USER located here, and that early chemistry lesson provided an elegant solution. If everything went to plan she could fire the CTDs down to their designated positions within the hour. Orlandine smiled to herself and, still linked via her carapace to the operation she was conducting, she availed herself of hot coffee from the spigot provided within Heliotrope’s interface sphere. It seemed almost inevitable that, at that very moment of relaxation, the ship’s detectors should pick up movement from the nearby surface installation.