 Complete the following phrase:  The navigations were used for transporting barge loads of heavy goods to London. Timber, corn, flour, wood and gunpowder from the Chilworth mills moved north along the canal and then down the Thames to London while coal was brought back principally for gunpowder making and smithery. Other return cargoes included sugar and bark, which was used for tanning. The trade in timber destined for the shipyards on the Thames had been established well before the river was canalised, and in 1664, 4,000 loads of timber were reported to have passed down the river. Much of the timber used in the reconstruction of London after the 