"Casement teaches Conrad that most often, it is better to trade with the men than the women because the women tend to bargain harder and are difficult to read. Many transactions take several days. Ivory is sold by weight and one must probe into the larger tusks with a sharp object because the natives have figured out how to load the tusks with lead. One good-sized tusk—a forty-five pounder—brings to the native trader a hundred gal- lons of rum, ten cases of gin, 400 yards of Manchester cloth, twenty kegs of gunpowder, four guns, and a bushel of other nonsense: buttons, beads, and baubles. Of course, the amount of these rubbishy goods required to purchase just one tusk of ivory surprises Conrad. He wants to know if every trader has to track such exchanges in specific detail, but Casement assures him that once he is up in the interior, that the quantities of ivory will require a different manner of transaction."
From VALIANT GENTLEMEN