REALLY nice unusual design antique printer's cabinet

by the THOMPSON CABINET COMPANY of Ludington, Michigan, fabricators of printer's furniture (see label in pictures)

This is unusual in that the compartments are set in on an angle rather than vertical or horizontal and gradually get deeper

It also has brass "buttons" down the left side and down the middle which start at the number 4 and end at the number 28.  All of these brass "buttons" are there (none are missing). 

I'm assuming the numbering is for print size and that the angled compartments have a very specific purpose, but I don't know what that might be.

Also, the cabinet and compartments are not very deep at the top and it angles down to quite deep at the bottom (see side picture).  The upper most compartment is just about 7/8" deep and the bottom most compartment is 5" deep.

Overall measurements of the entire cabinet are 30 1/4" high, 13 3/8" wide, the base is 5 1/4" deep and 14 1/4" wide.  The majority of the wood is quarter sawn oak with a lesser quality wood being used for the backing.