Produced by Chris Curnow, David Garcia and the Online Distributed Proofreading Team at http://www.pgdp.net (This file was produced from images generously made available by The Internet Archive) [Illustration] LECTURES ON VENTILATION: BEING A COURSE DELIVERED IN THE FRANKLIN INSTITUTE, OF PHILADELPHIA, DURING THE WINTER OF 1866-67. BY LEWIS W. LEEDS, Special Agent of the Quartermaster-General, for the Ventilation of Government Hospitals during the War; and Consulting Engineer of Ventilation and Heating for the U. S. Treasury Department. =Man's own breath is his greatest enemy.= NEW YORK: JOHN WILEY & SON, PUBLISHERS, 2 Clinton Hall, Astor Place. 1869. Entered according to Act of Congress, in the year 1868, by LEWIS W. LEEDS, In the Clerk's Office of the District Court of the United States for the Southern District of New York. New York Printing Company, 81, 83, _and_ 85 _Centre Street_, New York. PREFACE. These Lectures were not originally written with any view to their publication; but as they were afterwards requested for publication in the Journal of the Franklin Institute, and there attracted very favorable notice, I believed the rapidly increasing interest in the subject of ventilation would enable the publishers to sell a sufficient number to pay the expense of their publication; and, if so, that this very spirit of inquiry which would lead to the perusal of even so small a work, might be one step forward towards that much-needed more general education on this important subject. It was not my desire to give an elaborate treatise on the subject of ventilation. I believed a few general principles, illustrated in a familiar way, would be much more likely to be read; and, I hoped, would act as seed-grain in commencing the growth of an inquiry which, when once started in the right direction, would soon discover the condition of the air we breathe to be of so much importance that the investigation would be eagerly pursued. L. W. L. CONTENTS. LECTURE I.