The last home had been extremely pleasant of course, but on a quite different scale. They knew every inch of it blindfold, and were never allowed to explore anywhere beyond it. The nurses and maids who had them in their charge had all known their late mother and, naturally, adored her as everyone had. Their chosen method of respecting her memory had been to wrap her poor offspring in cotton wool. The children were not once allowed out without supervision, and every cough, shiver and sniffle had them confined to their quarters. They had been finding it increasingly tiresome.

The servants at Hatch, though, could not be more different. As the housekeeper did not mind explaining to Mary, the staff here had much preferred life under the previous incumbents – back when nobody asked to see ‘the accounts’ with the butcher or ‘the key’ for the wine cellar, and the nursery wing was just as it should be, shut up and dark. The last gentleman – God rest his soul – was not cold in his grave when, all of a sudden, they were expected to put up with the king in his counting house and his great rabble of children. Five of you devils! The servants, she said, had come to unanimous agreement: they would look after them as little as possible.

Mary Dorothea had never before known a minute’s neglect and – oh! – how she relished it. It was not just the hours – endless hours, sun-drenched and warm – of true freedom that opened before her. It was also the time with her brothers. For most of their lives, she had either been away or just somehow separate – expected to do something other or be somewhere else. But now, here she was: one of their number; part of the pack.

At last, Mary and John arrived, breathless, at the back of the boathouse. When they saw Norton already at work – head bent over wires; brown paper and bottles assembled – John cried out in dismay.

‘We missed it,’ he wailed. ‘They’ve done the a speriment!’

Norton, his brow low with concentration, looked up and snarled: ‘Course I haven’t, you fool. I’ve been wanting to electrocute you since the day you were born.’

Mary sank down to the earth, crossed her legs, patted her lap, pulled John down into it and rested her chin on his golden head. Gosh, but were not boys marvellous? She loved that frank contempt with which they spoke to each other, when girls always pretended to friendship while inside they were beasts. And fancy knowing all about electricity and galvanism, when she had but the haziest idea of what the words even meant. And imagine – just imagine – having the sheer nerve to try it out on all of your siblings! Mary was completely in awe.

‘Right, you lot.’ Norton looked up. ‘In a line with you. Now!’