All expenses of any impeachment proceedings, after the Legislature shall have adjourned, shall be paid out of any legislative appropriation made for the payment of the per diem and expenses of any such Legislature, and shall be approved by the presiding Justice of the court and attested by its clerk; provided, that before any such claim shall be allowed against any said appropriation, the person making the claim must first make and submit an affidavit that such services have been actually rendered, or such expenses incurred, under the provisions of this act.¹