Ask on the land, for there is no other successful method of dealing with it at present known, and therefore towns and villages have been empowered by various Acts of Parliament to acquire land for this purpose. Private persons have not this advantage and in their case the cesspool has always, until lately, been regarded as the only resource. But it is a very dangerous resource. how the liquid gets away from the cesspool and you will probably be told that it percolates through the brickwork forming the sides, the bricks being laid dry on purpose, and passes into the surrounding soil. Yes, percolates under our houses, into the springs, pollutes the wells, until, as at Rugby before the sewerage works were executed, things come to such a pass that the fluid thrown into the cesspool in the morning is pumped from the well at night! Or, perhaps, the cesspool is well built and the sewage retained in it, but the mass of putrid filth must be taken away, and I suppose many persons have been disgusted at some time or other with this sickening process. The remedy is not hard to find, but the means to be adopted will depend greatly upon the conditions of each individual case. Moreover, this belongs to another branch of sanitary science, and I am wandering away from ventilation. What has been said with respect to ventilating drains connected with sewers will apply with more force where there are cesspools. For in the former case there may be no evolution of foul and dangerous gases even for years, while in the latter it is certain and continuous. It is of no use to try and enclose it in the cesspool, free vent must be given if you would keep death and disease out of your houses. In concluding these somewhat disjointed observations on a very important subject, I would ask the reader to remember that the whole paper has been written at different times, when a few moments could be spared from more pressing matters, and if I have not adhered strictly to ventilation, pure and simple; yet drainage and warming are so intimately connected with it, that it is difficult to treat of one without drawing in the others also. Very much more might have been said about ventilating public buildings, such as churches for instance, where no attempt seems ever made to get fresh air in, or foul gas out of the building, but I have simply endeavored to convey a little useful information to the reader, which will, I hope, be of service in improving domestic comfort, and keeping disease away from our homes. Any book in this Catalogue sent free by mail on receipt of price. VALUABLE SCIENTIFIC BOOKS, PUBLISHED BY D. VAN NOSTRAND, 23 MURRAY STREET AND 27 WARREN STREET, FRANCIS. Lowell Hydraulic Experiments, being a selection from Experiments on Hydraulic Motors, on the Flow of Water over Weirs, in Open Canals of Uniform Rectangular Section, and through submerged Orifices and diverging Tubes. Made at Lowell, Massachusetts. By James B. Francis, C. E. 2d edition, revised and enlarged, with many new experiments, and illustrated with twenty-three copperplate engravings. I vol. 4to, cloth. .$15 00 ROEBLING (J. A.) Long and Short Span Railway TUNNER (P.) A Treatise on Roll-Turning for the 25 00 7 50 |