PREFACE. THE aim of the present Treatise on Hydrostatics is to develop the subject from the outset by means of illustrations of existing problems, chosen in general on as large a scale as possible, and carried out to their numerical results; in this way it is hoped that the student will acquire a real working knowledge of the subject, while at the same time the book will prove useful to the practical engineer. It is very important in Hydrostatics that the units employed should be kept constantly in view; and for this reason the condensed notation proposed by M. Hospitalier at the International Congress of Electricians of 1891 has been adopted. In this notation the full length expression of so many "pounds per square inch" or "kilogrammes per square centimetre" is abbreviated to lb/in2 or kg/cm2; and so on for other physical quantities. The gravitation unit of force has been universally employed, except in a few problems of cosmopolitan interest, in which the variation of gravity becomes perceptible. In accordance with modern ideas of mathematical instruction, a free use is made of the symbols and operations of the Calculus, where the treatment requires it, although an alternative demonstration by elementary methods is occasionally submitted; because, as it has well been said, "it is easier to learn the Differential Calculus than to follow a demonstration which attempts to avoid its use." Particular attention has been given to the applications of the subject in Naval Architecture, and the Transactions of the Institution of Naval Architects have been ransacked for appropriate illustrations. The diagrams, which have been drawn by Mr. A. G. Hadcock, late Royal Artillery, are intended to represent accurately to scale the objects described. No attempt has been made to rival the beautiful shaded figures of the French treatises, for fear of obscuring essential principles. A type of uniform size has been employed throughout: although adding considerably to the bulk, it is hoped that this uniformity will prove acceptable to the eyes of the readers, and counterbalance the disadvantage of the extra size of the book. |