Conversion of perishable property: trustees must convert wasting or future interests into permanent profitable assets unless contrary intent is shown. Trustees must convert wasting property, and future or reversionary interests held for successive beneficiaries, into permanent and immediately profitable property unless the trust instrument shows a clear contrary intention; absent such intention, trustees should sell wasting assets like leasehold houses and reinvest proceeds, but should not sell where the instrument explicitly directs enjoyment in specie.