David Gordon Wilson - Böcker

An updated edition of a classic: an indispensable companion for a new era in cycling.The bicycle is almost unique among human-powered machines in that it uses human muscles in a near-optimum way. This essential volume offers a comprehensive account of the history of bicycles, how human beings propel them, what makes them go faster—and what keeps them from going even faster. Over the years, and through three previous editions, Bicycling Science has become the bible of technical bicycling not only for designers and builders of bicycles but also for cycling enthusiasts.After a brief history of bicycles and bicycling that demolishes many widespread myths, this fourth edition covers recent experiments and research on human-powered transportation, with updated material on cycling achievements, human-powered machines for use on land and in air and water, power-assisted bicycles, and human physiology. The authors have also added new information on aerodynamics, rolling drag, transmission of power from rider to wheels, braking, heat management, steering and stability, power and speed, and other topics. This edition also includes many new references and figures.With racks of bikeshare bikes on city sidewalks, and new restrictions on greenhouse gas–emitting cars, bicycle use will only grow. This book is the indispensable companion for a new era in cycling.

Spiritualism and mediumship are often regarded as the product of lingering superstition in the Victorian era, and as having limited relevance in modern Anglo-American society. Scholarship to date which has considered Spiritualism as a distinct religious tradition has focussed on analysing the phenomenon in terms of spirit possession only. This volume analyses the development of shamanism (communication with the spiritual world) as a concept within North American English-speaking scholarship, with particular focus on Mircea Eliade's influential cross-cultural presentation of shamanism. By re-examining the work of Sergei Shirokogoroff, one of Eliade's principal sources, the traditional Evenki shamanic apprenticeship is compared and identified with the new Spiritualist apprenticeship. The author demonstrates that Spiritualism is best understood as a traditional shamanism, as distinct from contemporary appropriations or neo-shamanisms. He argues that shamanism is the outcome of an apprenticeship in the management of psychic experiences, and which follows the same pattern as that of the apprentice medium. In doing so, the author offers fresh insights into the mechanisms that are key to sustaining mediumship as a social institution.