Originally published in 1946, as the second edition of a 1936 original, this dynamic textbook is a companion volume to Ramsey's earlier publications entitled Dynamics and Statics and is primarily intended and written for sixth form and first year university students. The book covers elementary hydrostatics and 'constitutes a simpler course' for students on the subject. Topics covered include, 'the pressure of heavy fluids, centres of pressure, floating bodies, simple applications of the metacentre and of the general pressure equations, pressure of gases, the atmosphere, hydrostatic machines and, because no book on the subject can be considered complete without it, a short chapter on capillarity'. Notably, the examples have mostly been chosen from papers set in the Mathematical Tripos and in college and inter-collegiate examinations. Acquaintance with calculus is assumed. This book will be of great value to anyone with an interest in hydrostatics, physics and the history of education.