Entail Improvement Act 1770 (c. 51)

3 Lease for 2 lives, or more than 19 years, to oblige tenant to keep fences in repair, and to leave them so at expiration. Not more than 40 acres to be comprehended in one field, except where lands are improper for culture by the plough. S

And provided also, that every such lease for two lives, or for any term of years exceeding nineteen years, shall contain a clause obliging the tenant or tenants to keep and preserve the fences, when made, in good and sufficient repair during the lease, and to leave them so at the expiration thereof; and that no inclosures which shall be made, shall comprehend more than forty acres in one field; excepting where the lands consist of hills or other grounds incapable or improper by their nature for culture by the plough; in which case, the inclosures may be made of such extent as the nature of the ground shall require.