Collis buttoned up his pants. ‘Do you want to join me for breakfast?’ he asked. ‘I was thinking of ham and scrambled eggs at the Western Rooms.’

‘No, no,’ said Theodore. ‘I must make some preparations. I must tell Annie what clothes I’m going to need. I must get out my good theodolite.’

‘All right,’ said Collis. ‘When do you want to leave?’

‘It’s, what, Thursday today. We should set out on Monday morning. Don’t forget gloves, either.’

‘No,’ said Collis. ‘I won’t forget gloves.’

Theodore opened the door. Then he paused. ‘Oh, and one more thing. I know it sounds morbid, but I think it’s better to be well prepared for the worst. It can be dangerous up there, especially if it snows. So if there’s anyone you want to write to — well, it’s worth thinking about.’

Collis looked at him with a patient, indulgent smile. ‘You sure you don’t want me to take a shroud in my knapsack?’

‘It’s not a joke, Collis. Remember what happened to John Frémont’s expedition.’

‘Very well, Theo. I’ll write to my mother and sister, make a will, and order my headstone from Grosser and Buch. And in the meantime, I’ll go talk to Wang-Pu, and see what he thinks about coming along.’

Monday morning was bright, dusty, and windy. They drove out of Sacramento on a buckboard with ‘Tucker & McCormick’ painted on the side in faded black lettering. They had two fresh chestnut horses from the K Street stables, and enough blankets and coats and changes of clothes to last them for two weeks. Collis wore a wide-brimmed, low-crowned hat and a brown wool coat, while Theodore was dressed in a blue cotton jacket he used to wear on the railroads and a straw Panama. Wang-Pu, who sat in the back amid all the bedding, looked as if he were going to his uncle’s wedding, in a black tailcoat and a tall black hat.

They didn’t say much as they travelled. They passed stubbled wheatfields and stands of rusting deciduous trees. Then, as the road climbed through Folsom and Rocklin, up the valley of the American River, it became winding and uneven and strewn with stones, and they jolted through the midday dust with aching backs and pained expressions of acceptance. Collis smoked, and wiped the sweat from his face, and occasionally took a swallow of sherry and whisky mixed, from a bottle he kept under the buckboard’s seat.