I do like getting my money’s-worth. Elevenpence-ha’penny the thing had cost me, and it would have been cheap at double. The advertisement on the outside of the box had said that its effects were “indescribably ludicrous,” and I can testify that it was no overstatement. Poor old Biffy leaped three feet in the air and smashed a small table.

“There!” I said.

The old egg was a trifle incoherent at first, but he found words fairly soon and began to express himself with a good deal of warmth.

“Calm yourself, laddie,” I said, as he paused for breath. “It was no mere jest to pass an idle hour. It was a demonstration. Take this, Biffy, with an old friend’s blessing, refill the bulb, shove it into Sir Roderick’s face, press firmly, and leave the rest to him. I’ll guarantee that in something under three seconds the idea will have dawned on him that you are not required in his family.”

Biffy stared at me.