was struck between the two losses of States. While Virginia
remained a slave State, it was natural that slavery should extend
into Kentucky, which had been a part of Virginia. Likewise
Tennessee, being a part of North Carolina, became slave
territory. When these two Territories became slave States, the
equal division began. There was yet an abundance of territory
both north and south to be taken into the Union and, without any
special plan or agitation, States were admitted in pairs, one
free and the other slave. In the meantime there was distinctly
developed the idea of the possible or probable permanence of
slavery in the South and of a rivalry or even a future conflict
between the two sections.

When in 1819 Missouri applied for admission to the Union with a
state constitution permitting slavery, there was a prolonged
debate over the whole question, not only in Congress but
throughout the entire country. North and South were distinctly
pitted against each other with rival systems of labor. The
following year Congress passed a law providing for the admission
of Missouri, but, to restore the balance, Maine was separated
from Massachusetts and was admitted to the Union as a State. It
was further enacted that slavery should be forever prohibited
from all territory of the United States north of the parallel 36
degrees 30', that is, north of the southern boundary of Missouri.
It is this part of the act which is known as the Missouri
Compromise. It was accepted as a permanent limitation of the
institution of slavery. By this act Mason and Dixon's Line was
extended through the Louisiana Purchase. As the western boundary
was then defined, slavery could still be extended into Arkansas
and into a part of what is now Oklahoma, while a great empire to