TRADES & ARITHMETIC. - A collection of mainly 18th century works including: John Thomson's The Universal Calculator; or The Merchant's, Tradesman's and Family Assistant (Edinburgh, 1784), Comes Commercii, or, the Trader's Companion (London, 1754), Richard Hayes' Interest at One View (London, 1781), William Leybourn's Panarithmologia or, the Trader's Sure Guide (London, 1756), Richard Hayes's A New Method for valuing of Annuities Upon Lives, and Leaseholds, or Leasehold Estates; Also, Church and College Leases Considered (Dublin, 1789). Sold not subject to return (12)