germs, particles, and spores of fungi, were found also in extremely minute quantities. But the important consideration is, that these germs, particles, and spores, the most dangerous elements of sewer-air, can not escape from the water-seal, and that the quantity of carbonic acid, and the accompanying gases arising from sewer-air, which, even under the worst conditions, can pass through water, is minute and utterly harmless. The experiments of Prof. Doremus were therefore irrelevant and valueless as applied to a determination of the efficiency of trap-seals.
It has been said, too, that Mr. Paton, a chemist temporarily in the employ of the health department of the city of Chicago, at one time observed the passage of sewer-gases through the seal of a trap. Since frequent reference has been made to this experiment, it is fortunate that the report of Mr. Paton is still accessible. An examination of the document in question, and of a drawing of the apparatus employed in the experiment, shows at once that the results obtained have no relation whatever to the subject we are considering. Mr. Paton, instead of trying to ascertain if gases would find their way unassisted through a trap-seal, adopted the very original method of forcing them through the water into a vacuum by atmospheric pressure. A more absurd proceeding could hardly be imagined, were it not for the fact that these experiments were in reality conducted to determine the value of a so-called germicide which the health officers had been asked to examine.
There is, then, absolutely nothing in the form of reliable testimony that can be brought forward to contradict in any particular the positive and comprehensive statements of the eminent scientific authorities previously referred to.
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| Fig. 4.—First Step in the Development of an Anti-siphonic Trap. |
It is established beyond question that water may be safely used as a seal for traps. But may there not be a better and more complete medium of resistance against sewer-air? The attempt has been made to substitute mechanical valves of various kinds in place of the water; a seal of mercury has also been employed, and, in some instances, balls of rubber and of metal have been used in conjunction with water; but these substitutes and additions have, in every case, proved extremely objectionable, on account of obstructing the outward flow of waste-water, and so causing accumulations of filth in the traps and water-pipes.
It is not at all probable, then, that any better contrivance than
