A new method of making the banks in the Fens almost impregnable [electronic resource] : So as in time to resist the force of rivers, in the most impetuous floods, and prevent all future inundations. With a new but certain method of preparing the lands therein, for the growth of our most valuable timber, viz. oak, elm, ash, &c. Particularly those extensive tracts of lands in the counties of Cambridge and Lincoln, &c. Also some observations on the River Cam; how to confine its bounds and improve its navigation; which may serve for a plan for any other inland river, &c. By John Harrison, botanist, nursery-man in Cambridge.