The first person to sail around Africa and to reach India ( and to get some precious spices from there!) was Portuguese Vasco da Gama, who did this in his journey that started in 1497 and reached India in 1498 ( and returned in 1499)
Answer:
The north used the rising number of immigrants to staff the industrial economy (factory jobs, warehouse jobs, etc...) the south felt no need to employ immigrants on their plantations because the invention of the cotton mill had made slavery a more economical option.