Now, look at THIS needle, with which the Professor was just going to prick my finger! You can see for yourself at once it is of bluer steel and of a different manufacture." "That is quite true," I answered, examining it with my pocket lens, which I always carry.

"I see the difference.

But how did you detect it ?" "From his face, partly; but partly, too, from the needle itself.

I had my suspicions, and I was watching him closely.

Just as he raised the thing in his hand, half concealing it, so, and showing only the point, I caught the blue gleam of the steel as the light glanced off it.