Who invented the chalkboard?

James Pillans, Headmaster of the Old High School of Edinburgh, Scotland, is widely credited for inventing the blackboard and coloured chalk which he used to teach geography. Mr. George Baron, an instructor at West Point Military Academy, is considered to be the first American instructor to incorporate the use of a large black chalk board into the presentation of his math lessons in 1801. However, it's probable that a few other schools had access to it, also.