LUDLAM, [WILLIAM]. Two Mathematical Essays: The First on Ultimate Ratios, The Second on the Power of the Wedge. London, 1770--The Theory of Hadley's Quadrant, or the Rules for the Consruction and use of that Instrument Demonstrated. London, 1771--Directions for the use of Hadley's Quadrant, with Remarks on the Construction of that Instrument. London, 1771. Together, 3 works in one volume. 8vo, contemporary half calf, boards rubbed; minor worming. 6 engraved folding plates.