298 



THE POPULAR SCIENCE MONTHLY. 



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 uttei'ly harmless. The experiments 

 of Prof. Doremus were therefore irrelevant and valueless as ap- 

 plied 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 re- 

 sults obtained have no relation whatever to the subject we are 

 considering. Mr. Paton, instead of trying to ascertain if gases 

 would tind 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 })rocee(ling 

 coidd harilly be imagined, were it not for the fact that these ex- 

 periments 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 testi- 

 mony that can be brought forward to contradict in any particular 

 the positive and comprehensive statements of the eminent scien- 

 tific authorities previously referred to. 



It is established beyond ques- 

 tion that water may be safely 

 used as a seal for traps. But 

 may there not be a better and 

 more complete medium of resist- 

 ance against sewer-air ? The at- 

 tempt has been made to substi- 

 tute 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 accumiilations of filth in the traps and water-pipes. 



It is not at all probable, then, that any better contrivance than 



Via. 4.- 



FlI'ST StIvP in TITF DrVELOVMENT OP 

 AN AnTI-SII'UOiNIC TliAl". 



