Altogether, I calculate that it will be at least four hours before they think of breaking open the door of the office, to see if he is there; so at the worst we have got four hours' start; at the best, ten hours.
"It is only half-past nine now.

We shall be at the mouth of the Sienne in three hours, or less.

It does not look above nine or ten miles on the map and, directly we get fairly out of the town, we will go as quickly as we can, for every minute is of importance.
"If we can get hold of a boat at once, we ought to be at Jersey soon after daybreak; although I am not very sure of that, for I believe there are all sorts of strong currents along this coast.

I remember one of the officers saying so, as we came down the Channel on the voyage out.

Of course, it will make a difference whether we can get a boat with a sail, or not.