Excerpt from An Elementary Treatise on Quaternions Expression of a vector by one symbol, containing implicitly three distinct numbers. Extension of the signification of the symbol 518. The sign defined in accordance with the interpretation of a vector as representing translation, 5 19. Definition of It simply reverses a vector, 5 20. About the Publisher Forgotten Books publishes hundreds of thousands of rare and classic books. Find more at www.forgottenbooks.com This book is a reproduction of an important historical work. Forgotten Books uses state-of-the-art technology to digitally reconstruct the work, preserving the original format whilst repairing imperfections present in the aged copy. In rare cases, an imperfection in the original, such as a blemish or missing page, may be replicated in our edition. We do, however, repair the vast majority of imperfections successfully; any imperfections that remain are intentionally left to preserve the state of such historical works.