was by no means instantaneous, as the like change seemed to be yesterday) the other men worked away without, as far as I could see, taking any notice whatever of what was going on.

I exclaimed slightly and started, and this attracted Signor Davelli's attention. He had been, I think, examining and preparing some instruments. "What do you see?" he said. I answered without taking my eyes from the glass. "A man over there disappeared and appeared again just as you did yesterday."

"Careless wretches!" he said, looking towards the place that I was observing.

"I suppose," I said, "that these substances which they are examining must be very deadly, for his mask fell off just before he disappeared, and I remember you said yesterday that what would kill us only drove you back into space."

"And you infer, I suppose, that if you had been in his place you would have dropped down dead."

"That is what I think," said I.

"Then you see if you become one of us you escape death." He said this with a strongly persuasive manner, and as he spoke a slight shudder seemed to pass over me, and I expected him to say more. But he said no more, and he returned to the task in which he had been engaged.