The probe itself was nothing more elaborate than a narrow tube of hard steel with a sharp bottom edge and a cutaway gap down one side, topped by a T-shaped handle that helped the user force it downwards, deep into the earth. Withdrawn, the gap in the probe's side displayed a core sample of the layered soil deposits. In our case, the dark silt that filled a ditch would show up very clearly against the surrounding soil.

It was tedious work, though, and ramming the probe down again and again through tangled turf and heavy subsoil demanded a fair bit of strength.

David flexed his broad shoulders and stifled a yawn, linking his hands behind his head. "It's a shame that Robbie can't go around and mark the ramparts for us. It'd save a lot of bother."

It was the first time I'd heard anybody tell me something Robbie couldn't do. "Why can't he?"

"Because he's not so accurate, with things like that. He has his hits and misses. Most of what he tells you he just gets at random, walking over things. If you ask him the right questions, he can tell you quite a lot. But if you push him, and he tries too hard..." David shrugged, dropping his hands again to reach for his coffee mug. "He's only a lad, not some kind of machine."

I studied him a moment, weighing my next question. Since coming to Rosehill, I'd grown used to David keeping his distance, polite and professional, his manner not inviting any personal intrusion. But Saturday in the kitchen with Jeannie, and now again this morning, he'd been so easy to talk to that I thought he might not mind if I just asked for his opinion.

"David ..." I found I liked the feel of his name, familiar on my tongue.

He drained his coffee, pulling a face at the taste. "Aye?"

"You're a scientist."

"Aye?"

"Well..." I steepled my fingers, and frowned. "How do you explain what psychics do?"

"I can't."

"But you believe in them."

He swiveled slowly in his chair, considering the matter. "That depends what you mean by belief. If you mean, do I accept the concept without question... no, I don't. But questioning things is the root of all science. Something happens we don't understand, so we test it, experiment, study the evidence."

"And is there evidence?”

“Oh, aye. You want to have a chat with a friend of mine who lectures in our psychology department, at the university. Did his Ph.D. mainly on parapsychology—he's been studying psychics for years." David's eyes touched mine, smiling. "He'll take you right back to the Oracle of Delphi, if you've the patience to listen. Thousands of years of reported occurrences. Mind you, it's only been since the last century that anybody took a scientific interest. The Society for Psychical Research, and all that. Flash cards in the laboratories."

I frowned harder. "But I still don't understand how Robbie—"

"Robbie sees things that the rest of us can't. You can test him any way you want to, laboratory or no, and you'll get the same result." He lifted one shoulder, dismissively. "It's uncomfortable, aye, when a thing won't fit into our orderly world, but then Western society's always been skeptical. And not very bright," he reminded me, wryly. "It took us till the sixteenth century to figure out the earth went around the sun."

He had a point, I thought. "So you're saying I should just accept the fact that Robbie's psychic."

"Christ, no. If we didn't have doubts we'd have no science at all, no reason to experiment. I'm only saying you should keep an open mind."

I promised to do my best. "And does the head of your department... what's his name? The one who's coming to lunch at the end of the month."

"Dr. Connelly."

"Right. Does he also have an open mind?"

"What d'ye mean?"

"Well, if we told him Robbie saw a Roman walking on the hill.. ."

"He'd have us all committed." David grinned. "No, we'll have to find some harder evidence, before Connelly will give his approval."

"I do wish we had more time."

"We've got two full weeks yet, lots of time. Besides, we're very close to something. I can feel it in my bones."

"You sound like Peter.”

“Aye, well, it rubs off on you, after a while. And I was howking with Peter afore I could walk."

"Howking?"

He shot me a mischievous glance. "D'ye not have your dictionary with you? My mother said you were fair having fun with it on Sunday."

I couldn't help smiling back. "Sorry, no, it's back at the house. What's 'howking"?"

“Digging. To howk something means to dig it up out of the ground." He lifted his coffee mug again and grimaced. "God, that's awful stuff. I'll make another pot. Did you want a cup, as well?"

"Yes, please, if you don't mind. Cream and sugar."

"Right." David rose and stretched to his full height before disappearing in the direction of the common room, and while I waited for him to return I carefully arranged the four new potsherds on my desk and bent over them, thoughtfully.

The furtive pad of footsteps broke my concentration.

I felt the hair rise prickling on the back of my neck, and glanced up sharply, seeing nothing. "Hello?"

No one answered. The silence stretched my nerves to breaking point, and when I felt the brush of cold against my hand I nearly shot straight up into the rafters. Recovering, I looked down at my hand and the thing that had touched me. A pair of liquid brown eyes stared back in mild inquisition, and Kip's long feathered tail gave a tentative wag. Collies, I thought, always looked so damned intelligent, and this one appeared to be weighing the wisdom of making friends with someone this jumpy and unpredictable.