I heard my uncle calling me as I came in, and found him very impatient.

"Did you get them all?" he asked, as soon as he saw me.

"Yes; after some trouble," I replied.

"Where are they?" he inquired.

"Here," I said, and I handed him the bag.

He took it without a word, and immediately retired into his private room.

During his absence, I busied myself in the laboratory in putting everything in order. I worked away for a long while—how long I can not exactly tell—when suddenly I heard an explosion in my uncle's little room, followed by a cry.

I rushed to the door and knocked.

"What is it?" he growled.

"What is the matter?" I cried.