PLUMBING 



4711 



PLUTARCH 



will draw out all the water if a vacuum is 

 formed in the waste pipe. To prevent this 

 there should always be a vent, unless a truly 

 siphon-proof trap is used. There are a few such 

 traps approved by plumbing inspectors, but 

 many others are falsely so-called. Venting 

 adds very much to the expense of plumbing, 

 but is too important to neglect. The second 

 danger to a trap is that its seal may be forced 

 out by pressure of gases in the sewer, but this 

 is not liable to occur if the vertical stacks 

 (main drainage pipes) end above the roof. 

 A third danger, from evaporation, is present 

 only when a fixture is seldom used. 



Every fixture, even an ice box, should have 

 a trap. Because it contains food, an ice box 

 should be specially protected by having two 

 traps with an open drip pan between. But 

 there should never be two traps in succession 

 without the intermediate opening, for what is 

 called an air-lock will eventually prevent drain- 

 age through the pipes. Where a bathtub or 

 other fixture has an overflow outlet, this must 

 never be connected to the sewer side of the 

 trap. Each trap should have an accessible 

 clean-out, but this should be on the under side, 

 where, if it is leaky, no gas can escape. Main 

 traps, at the point where the drain leaves the 

 house, are omitted in some cities in order to 

 ventilation to the general sewer, but the 

 omission is opposed by many sanitary engineers 

 because it may cause the gases of the sewer to 

 be forced out when there is a leak in the house- 

 hold pipes, or whenever a fixture trap is re- 

 moved or opened for cleaning. A main trap, if 

 installed, must have a fresh-air inlet. 

 Stacks should never enter the house drain at 

 it angles, and above the roof they ought 

 Iways to JDC at least four inches in diameter, 

 escape being frosted over in cold weather. 

 Testing for Leaks. The tests required by 

 I umbing inspectors in cities should be per- 

 formed wherever possible. The commonest are 

 water test for new houses and the smoke 

 peppermint tests for old ones. Each test 

 made twice, first when only the rough plumb- 

 is in place, afterwards when all the fiv 

 installed. In the first, of course, all ends 

 pipes are plugged, in the second all traps 

 given a seal. The water test consists in 

 li' system with water, gradually, so 

 leaks may be discovered as soon as they 

 ir. then allowing the water to stand several 

 irs. In the smoke test heavy black smoke 

 is introduced into the pipes and air pressure 

 then applied. The peppermint test depends 



upon the penetrating odor of two ounces of 

 oil of peppermint mixed into a gallon of hot 

 water. This is not so reliable as the smoke 

 test. C.H.H. 



Consult Gerhard's House Draining and Sani- 

 tary Plumbing; Starbuck's Standard Sanitary 

 Plumbing. 



PLUMMET, plum'et, a weight let down at 

 the end of a cord to sound the depth of water 

 or of excavations, or to regulate work such as 

 measuring, by keeping it plumb, or in a straight 

 line. In building a wall the plummet is con- 

 stantly used by masons. It usually consists of a 

 line fastened to a narrow board at one end and 

 at the other end to an egg-shaped piece of lead. 

 The weight of the lead keeps the line straight, 

 giving an accurate measure for maintaining 

 the perpendicular. If used near a range of 

 mountains the plummet is found to be incor- 

 rect, the attraction of the mass of mountain 

 drawing the metal weight slightly out of line. 

 The difference caused by this attraction, while 

 slight, would be sufficient to throw a high wall 

 quite out of the perpendicular. The attrac- 

 tion, therefore, in such cases has to be allowed 

 for that the building line may be kept accu- 

 rate. It is also stated that on the seacoast the 

 ebb and flow of the tide have a direct influence 

 on the plummet. 



PLUSH, a material similar to velvet, but 

 with a longer, softer nap. The nap was for- 

 merly always of mohair, the hair of the angora 

 goat, but silk is now commonly used. Worsted 

 plush with mohair nap is used in making cloaks, 

 caps, hats, and other articles of wearing ap- 

 parel. Plush with a silk nap is used for men's 

 silk hats, for ornaments on women's hats and 

 dresses and in upholstery. In Europe plush is 

 extensively used for breeches worn by footmen, 

 and for this purpose is made in a variety of 

 colors. London and Lyons are particularly 

 noted for the manufacture of plush. 



PLUTARCH, ploo'tarck (about A.D. 48- 

 about 125), a Greek biographer and essayist, 

 born at Chaeronea, in Boeotia, near the homes 

 of Hesiod and Pindar. He was educated at 

 Athens and by travel through Greece, Italy and 

 Egypt, in which countries he apparently had 

 access to numerous libraries and records. In 

 his old age he was the religious or ethical guide 

 to a large number of young men and was con- 

 sidered one of the most entertaining talkers of 

 his day. 



His Parallel Lives of Illustrious Greeks and 

 Romans, commonly referred to to-day as Plu- 

 tarrh't Lives, were written generally in pairs, 



