664. Cromwell was a great promoter of agriculture and the useful branches of gardening, and his soldiers introduced improvements whenever they rested any time in a place. The principal writers on rural subjects at this period appear to have been Captain Walter Blith and Samuel Hartlib. Blith's plan of improvement consisted chiefly in irrigation and drainage; but he also recommends ploughing, and compounding various soils with the earth. Hartlib recommends the adoption in England of the two secrets of Flemish husbandry, - that of letting farms on improving leases, and cultivating green crops.