12 THE POPULAR SCIENCE MONTHLY. 



A no less serious evil is the corrosion of lead traps or lead waste-pipes, par- 

 ticularly in old houses which have imventilated drains. This may he caused by 

 the action of sewer-gas, so called, or from the use of certain popular disinfecting 

 fluids. 



Lengths of pipe have been found completely honey-combed in this way. As 

 such corrosion usually occurs on the upper side of traps or horizontal pipes, it is 

 not easy to detect their presence from the absence of leakage, and the only safe- 

 guard is to avoid carrying waste or soil pipes horizontally ; also, to extend their 

 upper ends through the roof, and leave them open for ventilation. Lastly, to 

 substitute iron pipes for lead wherever possible, which is now the general rule 

 in all good plumbing practice. . . . Corrosion sometimes occurs at the joints of 

 lead pipes, contiguous to the line of solder, and is attributed to galvanic action 

 created by the contact of the zinc and lead, but as these openings are apt to 

 leak they are more liable to discovery. 



It is a good plan to overhaul all plumbing periodically, say once every year 

 or two, to guard against accidents. . . . And here it should be remarked that 

 sewer-gas is created not in the sewers alone, but every inch of waste-pipe in a 

 house, even though used to convey nothing but soapy water or the waste of 

 melted ice from a refrigerator, can, and commonly does, produce foul gases. 

 The worst odors are from just such sources, and they are certainly unwhole- 

 some. 



Moreover, it must always be remembered that no plumber's work, however 

 complete it may be at first, can be relied upon to remain perfect. ( u Medical 

 News and Abstract," November, 1881.) 



Says Mr. Collins, in " The Sanitary Record," London, for March 



15, 1882 : 



One hint more with regard to the house and its belongings, worth all the 

 rest : Do not imagine that when structure, drainage, water-supply, and the 

 various appliances appertaining thereto, are left in perfect condition, they will 

 always remain so, and that, unlike every other production, they will last unim- 

 paired for ever, or even that period of " for ever "a few years. 



The best plumbing will not, the experts say, last "for ever" ; but, 

 in order to render our houses perfectly safe, it ought to last as long 

 as the house will last, for we can in no other way know when the 

 danger is upon us. " It will not last that period of for ever a few 

 years," says Mr. Collins ; and Mr. Wingate says it should be " over- 

 hauled every year to two, to guard against accidents." Mr. Wingate 

 has told us what he means by "overhauling" the plumbing, when he 

 said to the Academy that no inspection of the plumbing of a house 

 was of value unless it was overhauled from top to bottom. In no 

 other way could he give the occupant a guarantee that all was right ; 

 because, where one defect was found, the chances were that there 

 were many. This, we are then given to understand, is what should 

 be done " every year or two." 



But we may be permitted to ask why the time should be fixed at 

 a year or two ? A leak might arise from any one of the many causes 

 enumerated to-day, which did not exist yesterday. Why, then, " to 



