Section 85. If clam bait is sold by the barrel, ”barrel” shall mean a fish barrel of not less than twenty-eight nor more than twenty-nine gallons, and containing twenty-six gallons of clams and not more than three gallons of pickle. If the purchaser and seller disagree as to the quantity in a barrel, either party may have it measured by the deputy director of standards or a sealer of weights and measures. If such barrel does not contain the said number of gallons of clams, the seller shall receive payment for the number of gallons of clams it does contain, but shall pay the expense of measuring and coopering; otherwise the purchaser shall pay such expense.