All moneys derived from the sale of the lands and land scrip accruing to the state by virtue of the act of congress approved July 2, 1862, entitled “an act donating public lands to the several states and territories which may provide colleges for the benefit of agricultural and the mechanic arts,” and income and interest received on account of the capital of the agricultural college fund, constitute the agricultural college fund, which is a separate and perpetual fund and shall remain forever undiminished. Agricultural college fund income, interest and revenues do not include expenses deducted from gross receipts permitted under ss. 24.04 (2), 24.53 and 24.62 (1). If this fund is by any action or contingency impaired, a state tax is hereby levied sufficient to replace the same, to be collected with the state taxes for the next ensuing year and paid into this fund.