•Pipe dealers are financially interested in maintaining the elaborate system of piping required by back venting and main house trap installation, while plumbers have nothing to gain by it, but rather much to lose, since what money goes into unnecessary piping is lost for better fixtures and more of them, and the public, alarmed by all the complication, becomes distrustful of all plumbing and tends to do away with its benefits as far as possible.

† In spite of these discouragements, some words of recognition have now and then been received from disinterested parties which have given renewed courage and perseverance at times when they seemed most needed. Among them are the following from no less of an authority than William E. Hoyt, C. E., S. B., Chief Engineer of the Buffalo, Rochester & Pittsburg Railroad Company and at one time chief engineer of the Massachusetts State Board of Health: "Not long after the adoption of the fallacious device of back venting, it became evident that more efficient means of guarding against the investigations. If they are actually improvements on what existed before (the need of improvement being clearly recognized) then they are the best in the particular class to which they belong up to the date of their presentation, and as the purpose of this writing is to advocate the best, they will necessarily have to be described as such irrespective of their authorship, and even in some cases to the exclusion of other things in the same class, which are believed to be not so good. It must be left to the common sense of the reader to judge of the soundness of the reasoning in each case, and of the just motive and sincerity of the author. The quotations in the foot-note are only given for the purpose of placing the reader, who might naturally be prejudiced by these circumstances, in a more impartial and receptive frame of mind for judgment.

It should be added that these investigations and innovations have been made in the course of regular professional practice, and have, therefore, been conducted in the unprejudiced spirit of an architect working for the interest of his clients, and in some cases with their substantial aid and co-operation. The improvements and their protection, are the result and not the cause or original purpose of the dangers of sewer-air were necessary and persistent effort was directed toward devising better methods of house drainage. The result has been the attainment of a new order of things by the recognition of scientific principles previously ignored. Without referring now directly to the experiments and investigations, we may consider briefly certain principles which have been established by them. The first and cardinal principle of science as applied to house-drainage is simplicity. In the place of a wilderness of pipes tangled in hopeless confusion about every fixture, modern science demands that there shall be only a simple and positive system which shall act with directness and certainty in every case. The old air pipes from traps are discarded. There are fewer joints and the danger from leakage is lessened. Instead of traps that easily lose their seal, notwithstanding the relief pipes attached, traps are now used that in themselves will resist the hostile influences of evaporation and siphonage. The new system demands that basins, sinks, baths and water closets shall be so constructed as to act after the manner of flush tanks, and scour the whole system of waste pipes at each discharge. It requires that there shall be no hidden and inaccessible recesses in plumbing fixtures, where filth may collect and putrefy so as to become offensive and dangerous. The absolute prevention of serious evils is considered of far greater importance than means to palliate them.

For the development of this science credit must be given mainly to an accomplished sanitarist of Massachusetts, Mr. J. Pickering Putnam, whose experiments and investigations on subjects relating to household sanitation are unquestionably the most thorough and complete that have ever been put on record. The first of this series of experiments was made for the Board of Health of Boston in 1883. Subsequently, special demonstrations were shown before the Suffolk District Medical Society of Massachusetts, the Boston Society of Architects, and others. The results have been published in the "Boston Medical and Surgical Journal," the "American Architect," the "Sanitary Record" of London, and other periodicals." Wm. E. Hoyt, C. E., S. B., in an article on "Safety in House-Drainage," published in "The Popular Science Monthly," for July, 1888.

If Mr. Hoyt has been a little over generous In his words of encouragement, it will not be allowed to have a permanently injurious effect upon the writer's character, but be considered as in a measure offsetting the rebuffs received from others not so favorable to progress as Mr. Hoyt.

The late Col. George E. Waring, in an article published in the Century Magazine for December. 1884. on the "Principles and Practice of House Drainage." wrote of the writer's investigations and writings equally pleasantly, saying of them that "they certainly mark a very important step forward in sanitary literature."

In another place equally encouraging words by other well known authorities will be quoted, only enough here being needed to reassure the reader and cheer him forward in the study of this somewhat dry subject, if a treatise on hydraulics may be so designated.

An apology should be made for the name "plumbing," which has curiously enough been taken from the very metal, lead (Latin, plumbum), which we are learning should rarely be used in its unalloyed form in plumbing at all. Brass and iron are rapidly taking its place. Lead is inelastic, inert, feeble, treacherous, unreliable for plumbing and dangerous on account of the fire it requires in the house for its manipulation. The ancient alchemists called it Saturn. The modern plumber should modify this name to Satan, and debar his entrance and his fire altogether from the house.

To sanitary engineers one of the most important works which have been published in the last decade is the record and critical examination of the researches of bacteriologists entitled "Sewer Gas and Its Influence Upon Health," by H. Alfred Roechling, C. E., which the writer has freely quoted in these lectures, and for which he desires here to express his obligation. More recent and equally valuable are the researches in the same field of our own Professor Charles Edward A. Winslow, of the Massachusetts Institute of Technology, whose aid is gratefully acknowledged.* Thanks are also extended to Professor Edward S. Morse for his courtesy in permitting the use of his remarkably interesting sketches which have been taken from one of his masterpieces entitled "Japanese Homes and Their Surroundings," published by Harper Brothers, New York.

Also to William Paul Gerhard, C. E., for valuable aid in connection with furnishing copies of the plumbing laws of a very large number of cities and towns of the United States; to Mr. David Craig for many practical suggestions; Mr. Craig, while acting as President of the National Association of Master Plumbers and of its sanitary committee, has performed a valuable public service in furthering the investigations conducted for the committee by Prof. Winslow,f and later their publication; to the writings of Dr. Antoine. Magnin, Prof. H. W. Conn, Dr. Niel Carmichael, Mrs. and Prof. Percy Frankland, Viollet le Due, Col. George E. Waring, Dr. Teale, and many others whose works are referred to and duly acknowledged in the text, to "Domestic Engineering" for a number of valuable articles which have been quoted and credited where mentioned, and, finally, to Mr. Samuel Hubbard, Director of the North End Union, of Boston, through whose invitation the course of lectures forming the nucleus of this work, was given before his pupils. J. PICKERING PUTNAM.

535 Beacon St., Boston.

*The National Association of Master Plumbers has within the last few months through its Sanitary Committee, made some very important Investigations on the question of the carriage of bacteria by sewer air. This most careful and valuable work was entrusted to Prof. Winslow. and seems to entirely remove the doubts on the subject cast by the publication of Major W. H. Horrocks of the English Army Medical Corps, and corroborates the conclusions of Laws and Andrewes. Roechling and others. The work is being printed by the Master Plumbers' Association, and is a very valuable contribution by them and its author to the literature of the subject, and to the welfare of the public.

†These conclusions of Prof. Winslow as published in this report agree with and corroborate the results attained by the author and published in the "Inland Architect" of Nov. 8, 1908, and in "Domestic Engineering" in 1900, 1903. 1906 and 1908.