The man sitting in the iron seat did not look like a man; gloved, goggled, rubber dust mask over nose and mouth, he was a part of the monster, a robot in the seat. The thunder of the cylinders sounded through the country, became one with the air and the earth, so that earth and air muttered in sympathetic vibration. The driver could not control it-straight across country it went, cutting through a dozen farms and straight back. A twitch at the controls could swerve the cat', but the driver's hands could not twitch because the monster that built the tractors, the monster that sent the tractor out, had somehow got into the driver's hands, into his brain and muscle, had goggled him and muzzled him-goggled his mind, muzzled his speech, goggled his perception, muzzled his protest.
(John Steinbeck, The Grapes of Wrath)
What is cat’? Is it displaying a certain pronunciation for cat or does it mean something else?