Also there is a very good article called

"The Free Negro in Mississippi Before the Civil War" by Charles S.Snyder.It was published in the THE AMERICAN HISTORICAL REVIEW vol.32, no.4(JULY,1927),pgs 769-788.

It explains how Mississippi created laws that made it difficult for free people of color in Mississippi.For example laws were created that made it very difficult for a slave to become emancipated in the state of Mississippi.Laws were also created to stop free people of color from moving to or residing in Mississippi.

This is from the article paraphrased
Before 1842 there wasn't any difficulties in manumitting a slave in mississippi aslong as that newly freed individual stayed away from the state of mississippi once he or she became free. There are cases where people were freed in northern states then they returned to Mississippi and former land /slave owner left property to the newly freed people and the state of mississippi seized their property saying those people were still slaves.

If a slave was to be set free in Mississippi and remain in Mississippi the slave owner had to get legislative permissionfirst.:(
Allother manumissions were considered null and void. If the person was freed in northern states and returned to Mississippi they were considered a slave.They were also breaking the law by returning. Now all cases were different; Some people were allowed to stay others who returned had to pay a price ;(

The above statements were enforced in Mississippi by 1834. So as the years increased the number of free people of color in MS decreased.

I hope this helps,
Sincerely,
AC Johnson