6. Power to invest, notwithstanding drainage charge.

A trustee having power to invest in the purchase of land or on mortgage of land may invest in the purchase, or on mortgage of any land, notwithstanding the same is charged with a rent under the powers of the Public Money Drainage Acts, 1846 to 1856, or the Landed Property Improvement (Ireland) Act, 1847, or by an absolute order made under the Improvement of Land Act, 1864, unless the terms of the trust expressly provide that the land to be purchased or taken in mortgage shall not be subject to any such prior charge.