1. Ch. 129, Laws of 1955, establishes a new assessment date for all new or altered buildings, and the uniformity clause of the Constitution is not violated.2. Ch. 129, Laws of 1955, does not change lien date for real property taxes.3. Ch. 129, Laws of 1955, does not affect power to municipality to require building permits for construction under $500.00, whether ordinance passed before or after statute.