Actually, the letters in the boxes are a "W" and a "H" (NOT Whitehead & Hoag).
"W H, in separate scalloped-edge square cartouches (1898, no. 28744):
Wilhelm Hasselbach, Solingen. Registry class: 9b. Style: roman. Note: accompanied by ‘No. 21’."
GERMAN TOOL AND BLADE MAKERS
A guide to manufacturers and distributors, their trademarks and brand names, 1850–2000.
The information pertains to the tang stamp, NOT the actual pocket knife.
Here is the link to the information.
https://www.archivingindustry.com/cutle ... arks-1.pdf
It is a FANTASTIC source for information on German tang stamps, maker marks, etc.