Every delegate to the convention shall receive $10 for every day that delegate is in attendance at such convention, not exceeding 3, and in addition thereto, 10 cents for each mile necessarily travelled by the delegate in making 1 round trip from the place of that delegate's residence to Dover. The president, secretary and other officers shall receive such compensation as may be fixed by the convention not in excess of $25 for any such officer, in addition to their compensation as such delegates. Disbursements for the purposes mentioned in this and for other necessary expenses of the convention, when approved by the convention and signed by the president, shall be paid by the State Treasurer out of any moneys not otherwise appropriated. The expenses of holding a special election shall be borne as provided by law for the holding of a general election.