"That's a lie!" Jackson whispered.  "The Vixen, if that is what they call their airship, never showed up until a few days ago.  I tried to signal to the driver; or, rather, I did signal to him, but he ignored me.  This man Collins came in with the car more than two weeks ago, and went out in it, too, and the other white man remained.  The next time he came, he was in the Vixen."