"Perhaps it was a warning?" I suggested.

"Goodness me, Miss Auber," Morton barked a short laugh before continuing, "Then why destroy the building? No, no, Miss Auber, either the Baratarians were, as they say, 'in' on the whole thing - "

"Surely not!" I interjected. "The Prince rescued several people!"

"The prince is merely one Baratarian;" The Major pointed out, "there are others."

I considered this option for a moment. Royal politics did have a tendency to be complex; my recent acquaintance with one Theo von Hentzau had made that abundantly clear. I did not have much time to think about it, however, as the Major was still speaking.

"Or, of course," he said, "the explosion was set off by someone else in the building."

This - a guest who was really a spy; a disgruntled kitchen employee in the pay of Simpelstur; a thug disguised as a deliveryman - was more  my speed. "A most intriguing possibility," I allowed, "and, in fact, the one I am pursuing."

I fished Dahlia's small piece of card out of my reticule and passed it over to Major Morton.

"Have you any idea what this might be?" I asked.

"A piece of light cardstock with a smudged fingermark on it," Morton replied.

I resisted the urge to roll my eyes. "No, Major! What had the man stuck his thumb in, to make such a mark?"

Major Morton held the card up and tilted it, so that the light raked across it. He ran a thumb over the dark smudge, then nodded. With a smile, he lifted the card to his nose, and sniffed it.

"Graphite," he pronounced confidently. "Pure graphite."

"Graphite?" I questioned.

"The soft grey material in the middle of a pencil, Miss Auber."

"But that isn't a powder," I protested, "Unless you are proposing that this individual was doing a great deal of sketching and this is pencil residue."

Major Morton looked amused. "Powdered graphite is not at all difficult to obtain. It makes a fine lubricant. I do not use it in this shop, because it is also electrically conductive, and because, like any other powder, it does have the unpleasant habit of exploding if a cloud of the material in the air encounters a spark."

My eyes grew wide. "Graphite powder is explosive, Major?"

"Almost any powder is, you know. Flour. Dust. Why do you suppose grain elevators explode, Miss Auber? Anything flammable and sufficiently fine can cause an explosion – and graphite is carbon, just like coal."

"That is exceedingly interesting," I responded excitedly, my mind flying with ideas of a bomb made from writing supplies.

"It wasn't used as the explosive at the embassy, though," Major Morton said. My face fell - I could feel the excitement melting away and my features softening along with it. "It might have been used as a conductor or an insulator, but most likely, as I said, it was used as a lubricant and your man just happened to get some on his thumb."

I felt deflated. This option was not only much less exciting than a pencil bomb, but less likely to lead me anywhere but a dead end. "I thank you for your help," I said.

"You'll let me know if you apprehend that Simpelstur scoundrel, won't you, Auber?"

"Oh yes, sir. Of course," I nodded. I struggled to put any enthusiasm into my words. "And my superior has instructed me to remind you that you may contact him at any time."

"Perhaps when next I see him at my club, then. I shall pass him a note. Thank you again, Auber."

I curtseyed politely, and turned to let myself out the door. I had not made it two steps when the entire room shook with the terrible din of a huge explosion.