"Cowan's rapid Extractor." — The Encyclopedia Britannica, 1910

Cowan's Extractor

"Cowan's rapid Extractor." — The Encyclopedia Britannica, 1910

"Cowan's four-frame Extractor; interior." — The Encyclopedia Britannica, 1910

Cowan's Extractor

"Cowan's four-frame Extractor; interior." — The Encyclopedia Britannica, 1910