At the time of A Buss from Lafayette, pupils often used individual slate tablets to do their work in class. They were like miniature chalkboards, but used special pencils instead of chalk. Here is a pile of slate boards for sale at Colonial Williamsburg, with a cup full of slate pencils just behind it. Please note the cedar pencils that were another writing implement used at the time. In fact, Clara uses a pencil to write in her journal, instead of an old-fashioned but perhaps more poetic-sounding quill!
I, Clara Summer Hargraves, of Gould Hill, in the Township
of Hopkinton, in the State of New Hampshire, in the United
States of America, in the Western Hemisphere, in the World,
and in the Universe, do hereby take up my quill (well, pencil,
as I am writing this by the pond so I can cool my feet in
the water on this hot day) . . .