It shall be lawful for the Borough Council from time to time to lease the land comprised in Schedules 1, 2, 3, 4, 5, and 6 hereto, or any portion thereof, for a term of years not exceeding, for an agricultural lease, twenty-one years; for a lease of mills, water-way leases, water leases, or other rights or easements, forty years; or for a building lease, ninety-nine years; and for a repairing lease, sixty years:
Provided that on every such lease shall be reserved the best rent, or reservation in the nature of rent, either uniform or not, that can be reasonably obtained by public competition, of which reasonable public notice shall be given, with the time, place, and hour of such competition, in some journal circulating in the borough and printed and published therein, to be made payable half-yearly or oftener, without taking any fine or other benefit in the nature of a fine, and that every such lease shall be by deed or memorandum of lease, as the case may be, and every such lessee shall execute a counterpart thereof, and every such lease shall contain a condition for re-entry on non-payment of the rent reserved for a period of not less than twenty-eight days nor more than three months after it became due.