(30 ILCS 555/1) (from Ch. 29, par. 36)
    Sec. 1. The board of trustees or other officer in charge of every institution in the State of Illinois which is supported in whole or in part by public funds or which is owned by any municipal corporation or political subdivision of this State, who are authorized and required to purchase coal for fuel purposes in the operation of any such institution, shall be required to purchase and use coal which is mined in the State of Illinois, if the cost of coal mined in the State of Illinois is not more than ten per cent (10%) greater than the cost of coal mined in any other State or States, including the cost of transportation.
(Source: Laws 1937, p. 1207.)