Since last post have seen a couple cases. One has 1919 movement and marked W.W.Case mfg.Co. not wwcco. that was also used briefly by Wadsworth. So existed to 1920 from 1892 making more than 200,000 cases. 1895 mark and 1919 shown here.
Listed address was State St., Chicago. A 48 page catalog with 60 case samples exist from 1900+. Any info or images seem very scarce. Notice 1919 case marks are for 19&1/2 Karat. Any info or images would be much appreciated.