6. Extent of authority.

Apart from express instructions enlarging or limiting it, the implied authority of the auctioneer1 is a general authority to sell by auction2 and deal in the way usual and customary amongst auctioneers3. The authority does not extend so as to make the seller liable for injury caused by the auctioneer's negligence to a person attending the sale unless the seller has instructed the auctioneer to do any unlawful act or thing whereby the injury was caused