320 THE POPULAR SCIENCE MONTHLY. 



tliey should be given a fair chance to do their work by giving 

 them plenty of air. Where a closet is only three or four feet 

 from the soil-pipe, this ventilation is not necessary for keeping 

 the pipe clear ; but it is more than ever necessary to prevent 

 siphonage. It is only under such circumstances that I would use 

 a trap specially difficult to siphon and without ventilation ; but 

 such a trap should be cleansed every six months, for a tra^D which 

 will not siphon will collect filth. 



8. Whether the work be for construction or for repair, see that 

 skilled workmen are employed upon it. There is little difficulty 

 in finding in any large city a plumber who understands his busi- 

 ness and takes pride in doing good work. He probably will not 

 compete for contracts, and his prices may be from twenty to fifty 

 per cent higher than some other plumbers will demand ; but it is 

 wisest to employ the best men, accept their advice, and not grum- 

 ble about their bills. A competent sanitary engineer, by which 

 is meant a well-educated engineer who has made a special study 

 of water-supply, sewerage, house-drainage, etc., will make the 

 best drawings and specifications, but first-class workmen are re- 

 quired to carry these out ; and a class of plumbers is slowly 

 being developed who can make plans and specifications satisfac- 

 torily, and whose advice as to fixtures, etc., can be relied upon, 

 and such men should be sought for and employed, no matter what 

 their prices may be. 



House-drainage may also be considered from the point of view 

 of the man who wants to know whether the plumbing actually 

 in his house is in such condition that it is or is not worth while 

 for him to make changes or repairs in it. It may not be such a 

 system as he would put in if he were building a new residence ; 

 but he does not wish to incur more expense connected with it 

 than is absolutely necessary. If no offensive odors have been 

 perceived, and there has been no sickness in the house which 

 would give rise to a suspicion that the drains might be out of 

 order, he will usually be satisfied, and will not even take the trou- 

 ble to carefully examine the apparatus, and still less will he be 

 disposed to have it inspected and tested by an expert. If offen- 

 sive odors are perceived in the house, and cases of disease occur- 

 ring in it have roused suspicion in his mind, he will probably be 

 more inquisitive ; and, if the physician advises skilled inspection, 

 he will usually be willing to have this made. The essential 

 points to be determined by such an inspection are, first, whether 

 there is leakage from any part of the soil-pipe beneath the cellar 

 or basement ; second, whether there is any obstruction to the flow 

 of sewage to the sewer ; third, whether there is any leakage of 

 gas into the house from any joint or fixture ; and, fourth, whether 

 the soil-pipe is properly ventilated and the traps properly ar- 



