Electrical and scientific apparatus Trademarks Filed in May 29, 1924
POLYPHASE DUPLEX
Filed: May 29, 1924
(CALCULATING) SLIDE RULES
Owned by: KEUFFEL & ESSER COMPANY
Serial Number: 71197820
LOG LOG DUPLEX
Filed: May 29, 1924
"CALCULATING) SLIDE RULES
Owned by: KEUFFEL & ESSER COMPANY
Serial Number: 71197821
