There were perhaps three hundred prisoners here, Luke guessed, and a guard allotted to each squad of fifteen men. Not many guards for so large a number of convicts--but enough. The weird gravity of Vulcan had taken care of that, and the flashlight things they always carried--queer lights that would instantly neutralize the insulating property of his clothing and render a man helpless.
* * * * *
Luke was working high up on the slope, with rock drill and pick. The group to which he had been assigned was composed entirely of new prisoners, mostly white men, but with a few blacks and one coppery-skinned drylander of Mars. Whimpering, hopeless creatures, all of them; not worth his notice. All day he labored without speaking to any of them and t