a mathematical instrument, serving to work questions in gauging, measuring, &c., without out the use of compasses; merely by the sliding of the parts of the instrument one by another, the lines and divisions whereof give the answer by inspection.

This instrument is variously contrived, and applied by various authors, particularly Everard, Coggethall, Gunter, Hunt, and Partridge; but the most common and useful are those of Everard and Coggethall.