Slavery during the 17th century worked more like indentured servitude. The first blacks to come to the Americas were indentured servants. They worked off the debt of their passage and were given land following their servitude. The whole system of indentured servitude fell away after land resources became limited. Blacks were allowed to purchase their freedom, buy land, even some having their own slaves. As the colonies entered into the 18th century, the black population was increasing as slave labor became more important to the plantations. Increasing numbers coupled with slave revolts led to the creation of slave laws in many of the colonies. These laws made slavery lifelong and a status associated with birth to a slave mother. Though slavery was becoming less common in the British Empire, when the US became independent, slavery became a part of the new country's economy and social structure.
"I hope therefore that for our own sakes as a part of the people, and for the sake of posterity, we shall act heartily and unanimously in recommending this Constitution (if approved by Congress & confirmed by the Conventions) wherever our influence may extend, and turn our future thoughts & endeavors to the means of having it well administred."
The greatest change in the West that was brought about by railroad expansion was a drastically increased population size, since people could now claim land and travel far more easily.
Since you are developing an argument that would be 1450 and 1750
