PIPERACEAE 



which is equal to a fall of about 

 22 ins. in every 100 ft. 



The pipes vary from 8 ins. to 

 1 1 ins. in diameter, according to the 

 pressure, the smaller diameters 

 being used on sections where the 

 greatest pressures occur. Cast-iron 

 pipes are used for low-pressure 

 sections, but steel pipes are chiefly 

 provided where the pressure ex- 

 ceeds about 180 Ib. per sq. in. The 

 maximum pressure in any section 

 is 900 Ib. per sq. in. The piping 

 more or less follows the natural 

 contour of the ground ; where this 

 rises and falls, at each summit an 

 air valve is provided, encased in a 

 vertical dome with a small outlet 

 inserted in the pipe line. The valve, 

 actuated by a float within the 

 dome, opens when an accumulation 

 of air occurs ; but the moment the 

 air escapes, the water, rising to fill 

 the air space, lifts the float and 

 closes the valve. To provide 

 against loss of water in the event 

 of bursts, stop valves are provided 

 at suitable intervals. Many other 

 types of valve for various purposes, 

 as well as meters, are included in 

 the system. See Oil. 



Piperaceae. Natural order of 

 herbs and shrubs, widely dis- 

 tributed over the warmer regions 

 of the earth. They have jointed 

 stems, and the leaves are mostly 

 alternate or in whorls. The 

 flowers are small, disposed in 

 spikes or sprays. Many of them are 

 aromatic ; some produce acrid 

 resin or aromatic volatile oil. 

 There are about 1,150 species, 

 distributed o-ver eight genera. See 

 Betel ; Pepper. '*, 



Pipeline. Alkaloid contained 

 in black pepper. It is of a lemon- 

 yellow colour, and when dissolved 

 in alcohol develops the character- 

 istic pungent taste of "pepper. 



Pipe Roll. Term applied to the 

 Great Roll of the Exchequer pre- 

 served in the Record Office.London. 

 It contains the accounts of the 

 revenue collected by the sheriffs, 

 which were called pipes, either 

 because they were sent to the 

 crown office in cylinders, or because 

 of their tubular form when rolled. 

 The records go back to the reign of 

 Henry II, and are a mine of in- 

 formation on all matters relating 

 to the revenue of the crown, etc. 

 See Record Office. 



Pipette. Narrow graduated 

 glass tube adapted to deliver small 

 volumes of liquid and employed in 

 chemical analysis. The liquid is 

 introduced into the pipette by ap- 

 plying suction from the mouth at 

 the upper end, while the lower end 

 is dipped into the liquid. The upper 

 end is then rapidly closed by ap- 

 plying the finger. One kind of 

 pipette is adapted for delivering 



one volume of a liquid, while 

 another variety has graduations 

 throughout its length, and small 

 amounts of liquid 

 can be released by 

 relaxing the pressure 

 of the finger on the 

 upper end. 



Pipil. American 

 Indian tribe in S.E. 

 Guatemala and Sal- 

 / >. , vador at the time of 

 ( J 150 the Spanish conquest. 

 \/ ICC An early offshoot of 

 the ancient Mexican 

 people, speaking 

 primitive Nahuan, 

 they maintained 

 their independence 

 amid the Maya 

 civilization. Statues 

 and bas - reliefs of 

 Toltec type from 

 Santa Lucia Cozu- 

 Pipette. Types malhuapa are attri- 

 usedinchemi- butcd to them. See 

 cal analysis Nahua> 



Piping Crow (Gymnorhina). 

 Genus of birds forming a sub- 

 family of the crows. There are three 

 species, all re- ........... .__.. . 



stricted to 

 Australasia. 

 They have 

 black and 

 white plumage, 

 and are often 

 called Austra- 

 lian magpies, 



111 



pi Fing ow , the 

 they display white-backed species 

 great skill in 



learning to whistle tunes and to 

 talk, for which reason they are 

 popular as pets. Their food consists 

 mainly of grasshoppers and other 

 insects. 



Pipi Pods. Astringent seed- 

 pods of Caesalpinia pipai, used as 

 a dye-stuff, but inferior to those of 

 C. coriaria. See Divi-divi. 



Pipit (Anthus). Genus of small 

 passerine birds, related to the wag- 

 tails. Great Britain possesses four 

 species. The meadow pipit (Anthus 

 pratensis), the commonest, is to be 

 seen almost everywhere in the 

 country, running on the ground in 



Pipit. 



Anthus petrqsus, the rock 

 pipit of Britain 



PIQUET 



search of insects and seeds. The 

 tree pipit (A. trivialis) is migra- 

 tory, arriving in April and leaving 

 in Sept. In appearance it is 

 difficult to distinguish from the 

 meadow pipit. The rock pipit 

 (A. petrosus) is the only British 

 song-bird that lives among the 

 rocks on the coast, whore it feeds 

 on small crustaceans and worms. 

 The water pipit (A. spinoletta), 

 Richard's pipit, and the tawny 

 pipit are only occasional visitants 

 to the S. of England. The pipits 

 are often mistaken for larks, to 

 which they are very similar, and 

 are locally known as larks, e.g. the 

 tree pipit is called the woodlark in 

 Scotland and the meadow pipit 

 generally is the titlark. See Egg, 

 colour plate. 



Pippin. Name for many varie- 

 ties of apple, notably Cox's Orange 

 Pippin, Newtown Pippin, Ribston 

 Pippin. The word was once applied 

 to any apple raised from pips and 

 not by grafting. See Apple. 



Pip Ridge. Ridge of Macedonia, 

 Greece, a few miles W. of Lake 

 Doiran (q.v.). Fortified by the 

 Bulgarians in the Great War, it 

 was an objective of the Allies in 

 their final offensive in 1918. Its E. 

 slope was the scene of an attack by 

 British infantry on Sept. 18 to 

 distract attention from the flank- 

 ing movements of the Serbs and 

 French. See Doiran-Struma Front, 

 Fighting on the ; Salonica, Ex- 

 pedition to. 



Piqua. City of Ohio, U.S.A., in 

 Miami co. It stands on the Miami 

 river, 73 m. W. by N. of Columbus, 

 and is served by the Cincinnati, 

 Hamilton and Dayton and other 

 rlys., and by the Miami and Erie 

 Canal. Steel and iron goods, 

 woollens, furniture, etc., are manu- 

 factured. Founded in 1809, as 

 Washington, and given its present 

 name in 1823, Piqua became a city 

 in 1846. Pop. 15,000. 



Pique (Fr., quilted). Name 

 given to fabrics in which ribs 

 raised in high relief are woven 

 laterally. Washing dresses for 

 summer wear are customarily made 

 of cotton piques. 



Piquet. Card game known in 

 England in the 16th ceniury as 

 la ronfte and subsequently in the 

 time of Charles I as piquet. It is 

 played by two persons with 

 32 cards, the six down to the 

 deuce inclusive of each suit being 

 discarded from the ordinary pack. 

 The cards rank from ace, king, 

 queen, knave, ten, etc. ; the ace 

 counts the highest both in cutting 

 and play, and there are no 

 trumps. 



The cards are cut for seat and 

 deal, the lowest having the choice. 

 Each player receives twelve cards, 



