By the time Childermass is returned, Strange has found the driest, most withered pieces of straw in the pile. He separates them into two pieces, placing them on either side of the puddle. In theory, the spell should work. Substitute a mirror for another reflective surface, substitute the withered straw for the dead flowers, a recitation and presto, the spell to know what my enemy is currently doing.

Now here comes the hard part. Because, to Strange's annoyance, the spell didn't work. He's just staring at his reflection, not watching Norrell do...whatever he's doing back in London. Probably talking to Lascelles or something equally irritating. But he needs to convince Childermass that the spell did work if he wants to get him over here and transport the two at least to the general vicinity of the doctor's tent. What would Arabella think if she saw him like this, acting? He'd tried many professions before settling on magician but none of them had been actor.

Well, one way to find out just how good he is. Strange looks over at Childermass, looking smug and triumphant. "A spell to see what my enemy is doing," he explains, mad grin on his face, as he stands back up. "The first piece of magic I've ever performed, this time with slight moderations. Come over here and take a look. I'm sure you'll be interested at the results."

A technical truth: he'll be interested to see that nothing happened before Strange attempts to transport them out of there.