Protractor and parallel rule combined
1740-1750
Brass 18-inch rolling parallel rule with adjustable line spacing device
1866-1876
Parallel rule, Southern Railway
Rolling type of Parallel rule with octagonal ends
1907
Capt. Field's Improved RAF navigator's parallel rule by Dargue Brothers Ltd., 1939
1939
Parallel rule and protractor with index arm
1865-1875