It is clear, then, that, given the most favourable circumstances, the traveller might not only make his journeys pay their own expenses, but might clear a handsome profit. Yet how far these circumstances were made the most of is a question that has at present to be decided on negative evidence alone, the verdict on which must be that no case is made out. In leaving, therefore, the general estimates for details, both have to be put forward as net, subject to the mitigations already referred to. The fare from Dover to Calais was five shillings throughout this period. So invariable was this charge that when a certain boatman was suspected of being in league with the Roman Catholic seminarists in France because he conveyed across some ladies who were religious fugitives, he was considered not guilty on its being ascertained that he had charged them one pound each for the passage.[128] This five-shilling charge did not include the cost of boarding and landing when that required, as so often happened, the use of small boats, or of porters wading out. Between Flushing and Gravesend 6s. 8d. seems to have been the fare.[129] [Illustration: A PASSENGER-BOAT FROM PADUA] Among the reasons for the preference of travel by water rather than by land, one was economy. In the case of tolls, for example, the case has been exactly reversed. As locks did not exist there were no river-dues; but of highway-tolls plenty; moreover, it often cost something to cross a bridge but never a sou to pass under it. As for ferries, the ferryman occasionally made the passengers pay what he pleased by collecting fares in the middle of the river. Yet another reason which raised the cost of road-travel as against river-travel lay in the latter affording far fewer chances to robbers, which also told on the direct expense by eliminating payments to escorts.