(iv) pany every Rule, let not that be any Difcouragement; for the Reason of many of the Operations will naturally arife as you go along, from the Connection of the Problems themselves. But if a Youth be unwilling to proceed without a Demonstration of every Thing, he may as well refuse to move or eat, because he has not by him a full Explication of the Cause of Muscular Motion, and the Nature of Maftication and Digestion of his Food. Besides, many of the Rules • arise only from Algebraical and Fluxionary Processes, which are impossible for him to understand at present. The Young Geometer must therefore defer them till he has, by the following, or fome other Introduction, initiated himself into a Knowledge of the first Principles of this most excellent and useful Science; which, we flatter ourselves, he may eafily, and in a short Time, accomplith, by a careful Perufal of the following Work. 4 And, as most Solutions in Geometry require some Knowledge of Decimal Arithmetic and the Extraction of Roots, we have therefore judg'd it proper to prefix them, as necessary to be gone over by the Learner, before he enters fully upon his Geometrical Studies. To erect a Perpendicular on the End of a Right Line 73 76 The Explanation of such Characters as are generally |