(105 ILCS 5/15-18) (from Ch. 122, par. 15-18)
    Sec. 15-18. Copies of lost certificates or patents.
    Purchasers of common school lands, and their heirs or assigns, may obtain certified copies or certificates of purchase and patents upon filing an affidavit with the county superintendent in respect to certificates and with the Secretary of State in respect to patents, proving the loss or destruction of the originals, which copies shall have the effect of originals.
(Source: Laws 1961, p. 31.)