The bonds shall be delivered to the purchaser thereof only upon payment of par and accrued interest to the date of delivery thereof, together with any premium bid, if any. The proceeds of the sale of said bonds shall be deposited in the State Treasury of the State of Oklahoma, in a fund which is hereby created and designated the “Oklahoma Capitol Improvement Authority Fund,” where they shall remain subject to disposition to be provided for by the Authority, provided that the State Treasurer of the State of Oklahoma shall invest said monies in interest bearing direct obligations of the United States of America, or of the State of Oklahoma, and provided further that all such investments of said monies must be so made that the same may be liquidated in time to enable the Authority to pay, in due course, the valid indebtedness incurred by the Authority for the purposes set forth in this act.¹