The council of each and every city in the state, in addition to all other powers now possessed by it, is hereby empowered and authorized to set apart, appropriate, and expend, or cause to be expended, in such manner as it may deem best, from any funds in the city treasury available therefor, an amount not to exceed the sum of $300 annually for each 75,000 of population of such city for the purpose of aiding in the appropriate observance of Memorial Day on the last Monday in May of each year and in the annual commemoration of the noble and valiant deeds of the nation’s soldier dead.