STAM BUILDINGS VENTILATION OF BUILDINGS. I do not claim to have discovered any thing new in the art of ventilation. All I have endeavored to do in the following pages is to lay down principles, which shall be applicable to almost every case where ventilation is required. One object of the paper is to insist upon the great and increasing importance of the subject, and, if successful in this, I am satisfied that it will not have been read in vain. Before proceeding further, I think it will be desirable to explain what I mean by the term "Ventilation." Briefly, it is this,-a gradual, continuous and complete changing of the air contained in any structure, a substitution, in fact, of fresh air for foul, but so gradual a substitution that the motion of the air should be imperceptible. Of course, in factories, imperceptibility cases of sewers. and. underground railways, it is obvious that any method may be followed which, promises the most perfect results. The importance of the subject under consideration, which can hardly be overestimated, has been the constant theme of writers on ventilation; thus, Dr. James Johnson, in a work called "A Diary of a Philosopher," says that all the deaths resulting from fevers are but as a drop in the ocean, when compared with the numbers who perish from bad air. It is to the efforts of science that we must look for an alteration in so disastrous a state of things, and men of science may be assured that Society will ere long demand, not, as an eminent Philosopher is reported to have said, a new faith-we neither look for nor expect that-but a longer life, increased freedom from disease, and greater means of enjoying sound health while life lasts. I believe, we cannot doubt that much of the apathy manifested towards our subject |