Slim is at the top of the bunkhouse hierarchy because all the other men are simple unskilled workers or, in the case of Candy and Crooks, even lower than unskilled workers in the hierarchy. Slim is a skilled worker and not only handles all the horses but directs the work of all the men when they are out in the field.
When he had finished combing his hair he moved into the room, and he moved with a majesty only achieved by royalty and master craftsmen. He was a jerkline skinner, the prince of the ranch, capable of driving ten, sixteen, even twenty mules with a single line to the leaders. He was capable of killing a fly on the wheeler's butt with a bull whip without touching the mule. There was a gravity in his manner and a quiet so profound that all talk stopped when he spoke. His authority was so great that his word was taken on any subject, be it politics or love. This was Slim, the jerkline skinner. His hatchet face was ageless. He might have been thirty-five or fifty. His ear heard more than was said to him, and his slow speech had overtones not of thought, but of understanding beyond thought. His hands, large and lean, were as delicate in their action as those of a temple dancer.
The above description of Slim, which appears in the second chapter, contains some phrases that ought to provide you with a good hook. Slim was the prince of the ranch. He was capable of killing a fly on the rear end of a mule with his bull whip without even touching the mule. Since he drove teams with as many as twenty mules in pairs, it would be quite a feat to kill a fly on the butt of one of the lead mules. Evidently the lead mules were called "wheelers." The term probably means that when the front wheelers turned, all the other mules would have to turn with them.
Slim shows that he is in charge of all the other men when he first meets George and Lennie.
"Hope you get on my team," he said. His voice was very gentle. "I got a pair of punks on my team that don't know a barley bag from a blue ball."
Slim's authority in the field extends into the bunkhouse because of his natural dignity and the fact that he is a "master craftsman." When Carlson raises the question of putting Candy's old dog out of his misery, it is Slim opinion that seals the dog's fate. Although "Slim" is only a nickname, Crooks the stable buck, calls him Mister Slim. Slim is naturally in charge whether in the field or in the bunkhouse. When Curley makes the mistake of attacking Lennie and getting his hand crushed, it is Slim who immediately takes charge. He tells Carlson to get the wagon hitched up so they can take Curley into Soledad to find a doctor. Then while Carlson is going for the wagon, Slim saves George's and Lennie's jobs by persuading Curley to say that he got his hand caught in a machine. Otherwise, Slim tells him, they will tell everybody what really happened and everybody will laugh at Curley. Being laughed at is the one thing Curley can't stand.
It seems to me that your essay should give examples of how Slim is at the top of the bunkhouse hierarchy. His status seems to depend partly on his natural dignity but more on the fact that he is a skilled ranch worker and an experienced leader of men. Under better circumstances, Steinbeck seems to be hinting, Slim could have been a big ranch owner, or an important politician, or a rich businessman. What Slim lacks, along with all the other men, is an education. He only knows what he has taught himself the hard way.
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