The signatory states agree to appropriate for the salaries, office, administrative, travel and other expenses such sum or sums as shall be recommended by the commission. The Commonwealth of Massachusetts obligates itself only to the extent of $6,500 in any one year, the State of Connecticut only to the extent of $3,000 in any one year, the State of Rhode Island only to the extent of $1,500 in any one year, and the States of New Hampshire, Maine and Vermont each only to the extent of $1,000 in any one year.