PUBLIC LIBRARY 205642A ASTOR, LENOX AND TIDEN FOUNDATIONS L 3. GOSMELL, Printer, Little Queen Street, Holber PREFACE. THE general utility of a work of this nature superfedes the neceffity of a Preface. But it may be thought neceffary to say a few words concerning the manner in which the fubjects are arranged. In the rules in Vulgar Arithmetic, I have somewhat departed from the order generally followed, in order to render that science more intelligible, and eafy of attainment, to those who choose to go regularly through it. Almoft every writer on Arithmetic follows a different order in the difpofition of his work; though every one must be fenfible of the abfurdity of teaching those rules which depend chiefly upon fractions, as Practice, &c. before the learner is acquainted with the doctrine of Vulgar Fractions. It may be obferved, that any rule in Arithmetic may with equal propriety be attempted, when the learner is fufficiently skilled in the four fingle rules. The rules of Intereft are alfo placed under the chapter of Stock-holding; and Tare and Tret in that of Merchants Accompts, being more intimately connected therewith. In the chapter of Optics, I have endeavoured to render the practical part of that ufeful fcience as intelligible as poffible, avoiding all algebraical and mathematical calculations (though neceffary in complete fcientific A 2 fcientific treatifes upon this subject), in order to render it more perfpicuous. In each of the other fubjects, I have retained those parts which appeared to me the most effential, and rejected the fuperfluous: availing myfelf of the labours of others on each of the fubjects; though I have not quoted every author; as that would be attended with more difficulty than might be at first expected, and partake of a precifenefs unneceffary in the present work, It may be proper to mention, that I have endeavoured to infert all the modern improvements, in each of the fubjects, that appeared of any confiderable utility. The errors unavoidable in works of this nature, abounding with calculations, I have, as far as they occurred to me, corrected in this edition. The candour with which the former edition of this work was received, is at leaft fome argument in favour of its utility, as alfo confolation to its author; and tends to alleviate an afflicting difpenfation of Divine Providence: and render tolerable an uninterrupted confinement to his room, which has now continued upwards of eighteen years. Middle Temple, 7. Of the Rule of Three Direct, fingle 8. Of the Rule of Three Inverse, single 9. Of the Rule of Three Direct, double 10. Of the Rule of Three Inverse, double 11. Of Fellowship, fingle and double 12. Of Alligation, medial and alternate 3 |