What is the distinction between a public trust and a private trust?

What is the distinction between a public trust and a private trust?

The essential distinction between a public and a private endowment (trust) is that the beneficial endowments vests in an uncertain and a fluctuating body of the persons either the public at large or some considerable portion of it answering a particular description. On the other hand , in a private endowment the beneficiaries are definite and ascertained individuals .