When a mortgage has been or shall be given and filed according to law in the office of the secretary of the land office,¹ or lien indorsed on the patent for any tract or tracts of land, as security for the discharge of the claim of the Commonwealth thereupon, and where any tract or tracts so mortgaged, or where a lien has been or may be indorsed on such patent, have become or shall hereafter become legally vested in different persons, any one or more of such persons, or their legal representatives, holding a portion or portions in his, her, or their own separate right, or the rights of those whom they represent, may apply to the secretary of the land office, who shall ascertain the proportion of the amount due on said part, and upon payment of the amount so ascertained, to indorse the same on the mortgage or lien, and upon the deed or conveyance for the land aforesaid, which shall discharge the lien of the Commonwealth upon the land contained in the said deed: Provided, That the applicant aforesaid, his agent or attorney, shall make it appear to the satisfaction of the secretary of the land office, by the certificate of the deputy surveyor² of the county, on the return of a survey made by him of such part of a tract, that the remaining part of the land held under a mortgage or lien to the Commonwealth aforesaid, is sufficient to pay the remainder due on said mortgage or lien, and also shall produce a certificate of the commissioners of the proper county, of the assessed value of the said land: And provided further, That the exoneration of the part or parts aforesaid, shall in to manner affect the lien of the Commonwealth upon the remaining part.