A clear, introductory survey of basic scientific principles and natural phenomena intended for general readers. It begins by explaining sensation, causation, properties and the distinction between natural and artificial objects, then proceeds to physical topics—matter, weight, density, buoyancy, pressure, motion and energy—using water, air and steam as recurring examples. Later sections treat states of matter, heat and thermal change, gases and vapours, and methods of measurement, emphasizing observation, experiment, and reasoning as the means to uncover laws of nature and apply them to practical questions.