ment of the many Favours received, I humbly beg leave to Dedicate this Piece to you; and am with the greatest Regard SIR, Your most Obliged and moft Humble Servant THE PREFACE А С T HERE are fo many Books of Navigation already extant, that it may feem impertinent to trouble the World with a new One; especially fince fome good Mathematicians both at home and abroad, and many who were perfect Masters of the Practice, have written on this Subject. The former thefe being fond of ingenious Speculations, have general ly been too prolix on the Theory, and too short on the practical Part. Whereas the later have in a great Meafure neglected the Theory, and not being very folicitous about Language or Method, have delivered the practical Rules in fuch a Manner, as they cannot be easily comprebended, and much less remembred, especially fince there is feldom mention made of the Reafons on which they depend. But I am very far from finding fault with all the Books on this Subject; for there are fome very full both on Theory and Practice, against which, I have no other Objection but that they are too tedions to be taught, and too dear to be purchafed by most People. Youth Youth ought to learn the Elements from shorter Trea- tifes, and afterwards at their leifure should read gene ral Systems, in order to perfect them. For thefe Reafons, I have ventured to publish this Small Treatife; wherein I have made it my chief Bufi- nefs to keep a due Medium betwixt the two Extremes, into which the fpeculative Writers on the one Hand, and the practical ones on the other are apt to run. I have laid down all the ufeful Rules, and troubled the Reader with no more of the Theory than is necessary to explain them. I have also explained the principles of Menfura- tion, Surveying, aud Gauging, and fhewed how they are applied to Practice, in order that my Book might better anfwer the particular end for which it is defigned, namely the Inftruction of the young Gentlemen of Mr WATTS's As for the particular Contents of each Section, the Rea- der will find them at the end of the Book, and therefore they need not be repeated bere. I fhall only obferve, that I have defignedly omitted Great Circle Sailing, as be- ing only fpeculative, and depending on Spherical Trigo- nometry, which would require a particular Volume to explain it. There are indeed two or three Problems ne- ceffary in Practice, which depend on the Refolution of Spherical Triangles; but for the Solution of thefe, I have I know, fome are of Opinion, that the Demonftra- tions are not to be easily learnt by every Capacity, on which account they teach the Practice only. This Book is therefore fo written as to ferve for their purpofe likewife, because they may take the Rules alone without their Rea fons. It is true indeed, that there may be great Difficul ty in finding out a proper Demonftration, but after it is found, it is easier to be understood than that of which is the Reafon and therefore they who are not capable of them. And I am inclined to believe, that what is commonly attributed to want of Genius in the Scholar, is often owing to want of Method and Perfpicuity in the Mafter. In preparing this Treatife for the Press, I own myself obliged to Mr STIRLING, F. R.S. (of the Academy in Tower-Street) who on his firft feeing my Papers, fo far approved both of the Matter they contained and of the Order in which they were put together, as to think them fit to be made publick with very little "Alteration. I acknowledge myself alfo obliged to that most excellent Book of Mr HODGSON, entituled a Syftem of Mathematicks, which I take to be by far the most compleat Treatife on this Subject, both as to Theory and Practice. And on this occafion I cannot but take notice of a late Writer, who has accufed him and all Writers on Navigation of being guilty of a very grofs Error; which is, that they took Departure and Meridional Distance to be the fame. Indeed in Plain Sailing he took them to be the fame and is still of the fame Opinion, notwithStanding what has been faid to the contrary. But that be did not in other Cafes take them to be the fame will appear by the following Paffage of bis Book at the end of Mercator's Sailing."To give the Learner all the "Helps neceffary to a right Understanding of this "most useful Part of Sailing, I fhall endeavour (before I conclude this Part) to fet his Notions A right, concerning Difference of Longitude, Me"ridional Distance, and Departure; and let him "fee, that tho' thefe are fynonymous Terms in "Plain Sailing, conftantly fignifying the fame "thing, and in every Question are reprefented by "the fame Right Line, yet in the true Sailing they "are effentially different one from another; and "and in the fame Problem, are, as they really "fhould be, reprefented or expreffed by different Lines, and are of different Values. Now 1 W. MEADOW s, T. Cox, W. HINCHLIFFE, W. BICKERTON, T. ASTLEY, S. AUSTEN, L. GILLIVER, and R. WILLOCK. A Treatife of Continual Fevers: In four Parts. To which are added, Medicinal Observations: In three Books. Wherein are enumerated, the Diagnoftics, Prognoftics, and Events of the feveral Diseases incident to Human Bodies. By Jodocus Lommius. Tranflated from the Latin, by Thomas Dale, M. D. Ogilby's and Morgan's Pocket-book of the Roads, with their computed and measured Distances, and the Distinction of Market and Poft Towns, to which are added, several Roads, and above five hundred Market Towns: A Table for the ready finding any Road, City, or Market-Town, and their distance from London: A Sheet Map of England, fitted to bind with the Book. And an exact Account of all Fairs, both fixed and movable, in Alphabetical Order, fhewing the Days on which they are held. By William Morgan, Cofmographer to their late Majefties. The feventh Edition. M. J. Juftini ex Trogi Pompeii Hiftoriis externis Libri 44. Quam diligentiffime ex variorum exemplorum collatione recenfitig & caftigati: To which is added, the Words of Justin difpofed in a Grammatical or Natural Order, in one Column, fo as to answer, as near as can be, Word for Word, to an English Verfion, as literal as poffible in the other; defigned for the eafy and expeditious learning of Juftin, by thofe of the meaneft Capacity, with Pleasure to the Learner, and without Fatigue to the Teacher. With Chronological Tables accommodated to Juftin's History. And also an Index of Words, Phrases, and most remarkable Things. For the ufe of Schools, by N. Bailey. 2. Erafmi Colloquia felecta decem; or ten felect Colloquies of Erafmus, difpofed in the following Manner. 1. The original Text printed by itself, from the best and most correct Edition. An English Tranflation, as literal as poffible, difpofed in that eafy Method of the common conftruing Book to Lilly's Grammer. For the ufe of Young Scholars, by N. Bailey. A Rational Grammar; with easy Rules, in English, to learn Latin, compared with the best Authors in moft Languages on this Subject. By J. T. Philips, Preceptor to his Royal Highnels William Duke of Cumberland. The fecond Edition. Fundamenta Grammatices; or the Foundation of the Latin Tongue, in two Parts. By Nicholas Farmborow, School-Mafter |