Section 35S. There shall be established and set up on the books of the commonwealth a separate fund, to be administered by the commissioner of education, which shall be known as the Teacher, Principal and Superintendent Quality Endowment Fund. The fund shall consist of all revenues from public and private sources as appropriations, gifts, grants and donations and from the federal government as reimbursements, grants-in-aid or other receipts to further the purposes of the fund in accordance with sections 19B, 19C and 19E of chapter 15A. All revenues credited to the fund under this section shall remain in the fund and shall be expended without further appropriation for applications pursuant to said sections 19B, 19C and 19E of said chapter 15A. The state treasurer shall deposit and invest monies in said fund in accordance with sections 34, 34A and 38 of chapter 29 in such a manner as to secure the highest rate of return available consistent with the safety of the fund. The fund shall be expended only for the purposes stated in said sections 19B, 19C and 19E of said chapter 15A at the direction of the commissioner. On February 1 of each year, the state treasurer shall notify the commissioner of the projected investment earnings of the fund for the upcoming fiscal year. The treasurer shall authorize the expenditure of an amount not to exceed the interest earnings of the fund, or $3,600,000, whichever is greater. Not more than 42 per cent of expenditures from the fund shall be for the purposes stated in said section 19C of said chapter 15A in each fiscal year, and not more than 15 per cent shall be for the purposes stated in said section 19E of said chapter 15A.