It shall be the duty of the Assessor to make an assessment of the persons, dogs, and property within said Town subject to taxation, substantially in the manner and form in which such assessments are made by the Assessor of the County, and to return the same to the Council on or before the first day of July in each year; and for this purpose he shall have all the powers conferred by law upon the County Assessor. He shall receive a compensation for his services to be fixed by the Council, which shall not be increased or diminished during his continuance in office.