In order to assist in the support of the Interstate Legislative Reference Bureau, established by the American Legislators' Association to coordinate the work of the various state Legislative Reference Bureaus, and other official agencies dealing with legislative matters, the sum of four thousand dollars ($4,000) is hereby specifically appropriated for the fiscal biennium beginning June first, one thousand nine hundred and thirty-one. One-half of said appropriation shall be paid during each fiscal year of said biennium, in equal quarterly installments, on requisition drawn by the Auditor General. Warrants for such payments shall be drawn to the order of the Director of the Interstate Legislative Reference Bureau. Biennially hereafter an item of such amount as may be deemed necessary for the support of said bureau shall be inserted in the general appropriation law.