This portable slate  desk has  a wooden framed  slate with a fixed compartment with  a sliding lid  on the back which houses seven double- sided writing, drawing/pictures and alphabet boards. The boards would be taken out and one would slide into the bottom of the slate board on the front.  This would enable the pupil to copy it on the slate. The old label on the lid of the compartment says "Shepherds Portable Slate Desk' with a description on how to use it. This design was patented by  C.C Shepherd's January 1877 in USA.
It measures approx 26.5cms x 18.5cms .