This is a metaphor that likens the west riding men to sleuth-hounds, or, as they're better known, bloodhounds. bloodhounds are known for their determination and their extraordinary ability to track by scent. by saying that the west riding men are bloodhounds chasing after money, the author is attempting to paint a picture in your mind of the men being deadset on finding the object they're tracking, similar to a dog tracking a scent.
