A coordinator assembled from a T-square, a drawing board, two slide rules and certain machined accessories has been developed as an improvement on the simple but useful device previously described. The merits claimed for the present design are (a) compactness, simplicity in operation, accuracy and (b) ease of assembly from apparatus readily and cheaply available.
This paper includes a description of the device and some remarks on its design and use.
R. A. CASTLEMAN,JR., "AN IMPROVED COORDINATOR," J. Opt. Soc. Am. 16, 287-287 (1928)