What is the purpose of jacks speech at the assembly?

Jack's speech at the assembly serves to assert his authority and rally support among the boys. He emphasizes the need for hunting and the thrill of power, appealing to their primal instincts and desire for adventure. By positioning himself as a strong leader who can provide for them, he seeks to undermine Ralph's leadership and gain followers, ultimately shifting the group's focus from order and civilization to savagery and dominance.