The london gentleman's and schoolmaster's assistant [electronic resource] : containing 1. An easy, and very comprehensive system of practical arithmetic. II. Great variety of bills of parcels, Promissory Notes, and Receipts. III. An abstract of chronology. IV. An extensive geographical table, shewing the direct Distance, Bearing, and probable Time of Sailing from London, to the principal Places on the Earth. V. A number of original questions as exercises. The Whole designed Chiefly for the Use of Schools. By Thomas Whiting, Writing-Master and Teacher of the Mathematics near Westminster-Bridge, Lambeth.