Excerpt from The Mathematical and Other Writings of Robert Leslie Ellis: With a Biographical MemoirHaving undertaken with your sanction the publication of the writings of your lamented brother in a collected form, I may be permitted to address to you a few observations on the principles by which I have been guided in the fulfilment of an act of piety to the memory of a friend of many years, whom I shall ever remember with affection and veneration.The greater part of the writings contained in this volume had previously appeared in Scientific Journals, and Reports, some few in Educational Treatises. I have had no scruple whatever in reprinting these works, since their publication had already taken place by the author's own act or permission.About the PublisherForgotten Books publishes hundreds of thousands of rare and classic books. Find more at www.forgottenbooks.comThis 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.