§ 143. Management and appropriation of property. Trustees created under the provisions of this article shall have the custody and management of all the property of such corporation, and shall appropriate the same, so far as the terms, provisions and conditions of the donations will permit, for the purpose of aiding and instructing children, or for providing suitable grounds for such a public park or parks and properly preparing, beautifying, embellishing and keeping up and maintaining the same, or for furnishing and supplying such library with a suitable and proper edifice, rooms, furniture, books, maps, magazines and whatever may be necessary to make, keep up and maintain a good and complete library, or for one or more of such purposes, and paying the expenses of the trust. Demising lands donated to the corporation and investing and keeping money invested at interest, and using the rents and interest therefrom for aiding and instructing children or for park purposes or library purposes, shall be deemed to be an appropriation of such property for said purposes.