You will see that by sect. 7 ad valorem duties are to be
                     calculated according to the value of the article at place of
                     shipment. This no doubt establishes in effect a system of diff
                     duties. But it was shewn, when the last Customs Act, which
                     contained a similar clause, was

 under consideration, that
                     this mode of levying duties was adopted in some of the colonies
                     (6015 & 4650 
B Columbia); and in another case a Report of the
                     Customs Commissioners was sent here in which (I think) it was
                     stated that the practise was not objectionable. (5517 Treasury
                     Gambia.) These papers are sent on with 10834 
B. Columbia.