Augie is one of the members of Master Payne's Circus of Adventure. We first see him , but only in the background. His first lines don't come until , when he's seen proposing a test of his "Relativistic Pain Theory" on Zeetha and her sprained ankle. Zeetha understandably (and none too gracefully) declines to be part of this experiment, but the incident serves to establish that Augie is one of the Circus' many minor Sparks -- in his case, apparently a theoretical Spark. (The mind boggles.)
Augie doesn't spend as much time on stage as many of the Circus people, but he figures prominently in one very important episode. Augie joins the ill-fated Lars in riding out to Passholdt, which sits astride one of the main passes through the mountains, in anticipation of putting on a show there en route to Mechanicsburg. What they find there that this is not a place to do a Heterodyne show, to put it mildly. Augie and Lars nearly get cut off from the Circus in the melee that follows, which could easily lead to a fate literally worse than death for them, and plain old death for most of the others. However, Dimo, Maxim and Oggie unexpectedly come to the rescue -- no small thing for future plot development -- and all's well that ends well. Sort of.
Augie fades into relative obscurity after this, but he probably heads off to England with the rest of the Circus, with some hopes of living happily ever after with Wanda; we've heard from a that they're an Item.