On Wednesday morning, David took Franz and drove the lorry to the lumber yard in Schaffhausen. "We could have used the one in Unterhallau, but it's a small place, and everyone is interested in goings on. There'd be too many questions, and we don't want anyone suspecting anything. There's a lot of German sympathy."

Using the list of materials they had compiled for the shed and for the tunnel setts, they selected beams, planks, boards, spikes and nails, and had them loaded into the lorry along with a roll of tarred paper and ten square metres of slate. Farther along the street, they stopped at the hardware store to purchase a square, three hammers, a ripsaw and two crosscut saws. After adding hinges, a door latch and fastening screws, David paid for it all, and they headed back to the estate.

"We'll discover things we've forgotten as we need them." David laughed. "Always seems the way."

"But for those, you'll need only to go into Unterhallau. Small purchases will raise no suspicion." Franz tilted his head. "I'm impressed with the expertise of the Sappers. Sergeant Perrier is a whiz with geometry. I guess it's needed; the precision. Digging blindly and arriving where intended."

"Many of them were miners before the war, so they understand the nature of things down there. With mining, though, the digging follows the ore seams. With strategic tunnelling, it follows levels and angles calculated from surface readings using trigonometry tables. Sergeant Perrier was telling me they sight between candles to maintain their direction and the incline underground."

Back at Sonnenhang, David drove the lorry across the courtyard and down the gentle slope to the foot bridge. "This is as close as we can get, so we'll hand-ferry the supplies from here."

Georg soon had a work party organised, and David headed down to the site to see the progress, carrying a load as he went. Sergeant Perrier greeted him. "We've run lines of probes across this whole area, Sir. The solid chalk is five or six feet down over much of it, but we've found three domes that come to within two feet of the surface. We're standing on one of them."

He pointed to the trench. "Here it's just under a foot. We can scrape the topsoil off to provide you with a solid foundation for the tool hut and give us a clean tunnel entrance with a natural watershed."

David looked at the trench, then across to the edge of the vineyard. "This is a bit farther back than you had calculated."

"Only twenty-three feet, Sir. It's better to have a great entrance than to save a few feet of digging. Also, the hut will be on a spot where vines would have difficulty establishing. I was talking with Madam Meier a while ago when she came down for a look. She confirmed my thinking that a vine needs to be well established before it can work its roots into the chalk fissures."

David nodded his head as he examined the proposed site. "Let's begin, then, Sergeant. You organise the work of both teams and coordinate the building with your digging."

"Very good, Sir."

He turned to Georg and motioned to the pasture. "While Sergeant Perrier is running the construction site, I'll have you take those not involved and have them begin stripping the sod around here, preparing the land and disguising the tunnelling activities."

"Very good, Sir."

"Georg?"

"Sorry, David. Tough habit to break."

Saturday 30 October 1915

They sat in the mess after lunch on Saturday, and David had Sergeant Perrier give a briefing to the group on the progress with the tunnel. "As we continue down, the chalk becomes increasingly saturated, making the digging easier. The walls are still weeping as they slowly drain, dry and harden. The fissures are fine now with the depth. Looks like we can place setts only every ten feet. We've dug thirty-nine feet, and we're now only five feet short of completing the entry ramp."

He looked up and smiled. "It's going faster than estimated because of the water-softened chalk. We'll dig a sump at the bottom of the ramp to collect seepage, then we'll strike a horizontal drift — actually, a one degree incline to beneath the far tool hut. About a month before we begin digging the up ramp."

"End of November." David nodded. "I'm delighted with your progress. I thought you'd get much dirtier, though. The Sappers I saw at Ypres were mud-caked."

"Kicking wet clay while kneeling in clay soup is among the worst of conditions. Much of the Front in Flanders is in the clay deposits of coastal lowlands. To make it even worse, the enemy artillery and mortar shells keep shaking our works, and the gases from the explosives permeate the soil. We go through a lot of canaries. Speaking of which, have they arrived yet?"

"The last I heard is Monday afternoon. Is it safe for you to continue digging without them?"

"Until we get a distance along the main drift, but that's two or three days yet. Pumping fresh air to the bottom should be safe for a while. We'll monitor each other and act as our own canaries."

"Don't continue if you feel it unsafe." David turned to Sergeant Heiss. "Georg, tell us how the field preparation is going."

"We've the sod cleared from the construction site to the lower vineyard and have worked up the slope about sixty yards following the line of probes. Frau Eberhardt said to go no wider than the fifteen-foot soundings. We've been scattering the tailings from the shaft in the deeper areas toward the edges and mixing them in."

"Have you encountered any problems?"

"We could use another spade or two. The potato forks are awkward for cutting and lifting the turf, though great for breaking and mixing the topsoil."

"Thank you, I'll pick up two from town." David nodded at Second Lieutenant Moberly. "We'll now have Herman bring us up to date on the shed construction."

"After the Sappers had levelled the site for us and they'd started the shaft, we laid the sleepers and the floor with a trap door. Not a door, actually, but simply a movable cover. We've three stud walls framed, and we were on the fourth when we stopped for lunch."

"Have you all the materials required to finish?"

"We need a drill for the slate and copper nails to attach them to the roof battens, the steel ones will quickly rust. Also, it looks like our calculations were a bit tight on the clapboard sheathing, so we'll cut carefully."

"I'll pick up a drill and nails when I go in on Monday. Also a few more boards." He scanned the faces in the room and smiled. "I'm very pleased with the progress." He swept his arm over the group. "We're twenty-four here — that's two rugger teams and two referees, and the hay's just been removed from the meadow over by the hedgerow. Let's spend the afternoon playing."