It shall be the duty of the Sergeant, at least once in six months during his continuance in office, and oftener if required by the Council to render an account of the taxes, fines, penalties, assessments and other claims in his hands for collection, and return a list of such as he may not have been able to collect by reason of insolvency, removal or other causes; to which list he shall append an affidavit that he has used due diligence to collect the claims therein mentioned, but has been unable to do so; and if the Council shall be satisfied of the correctness of the said list it shall allow him a credit for said claims; but may thereafter take such lawful measures to collect the same as shall be by it prescribed. He shall receive for his services in the collection of taxes, assessments and other claims due the Town, a compensation to be fixed by the Council, not exceeding five per centum on the amount duly collected and accounted for, except an additional per centum may be allowed in case of fines, and may be allowed in addition, a salary of not more than three hundred dollars per annum. He shall pay any more money in his hands belonging to the Town upon the order of the Council.