PLUM. 128 PLUMBING. chard, iind wood ashes on soils deficient in potash and lime. Most varieties of pluuis tend regularly to overlwiar, and thinning lias been found neces- sary to secure the finest fruit, especially «ith the American varieties. The plums arc left to stand two or three inches apart. They are mar- keted as soon as they become well colored. In the Vnited .States the eight-pound gra|)e basket makes one of the most satisfactory packages. Plim Disea.sks. Plums and cherries are often attacked by the same fungi. Leaf blight or shot liole is due to the presence of one or both of two fungi, Cj/liiKlrospoiium padi and Septoiia vera- sinn, in the leaves, the symptoms being alike on both i)lum and cherry. Circular i>urplish spots one-eighth inch in diameter api)ear: later the tissues become brown and break out from the leaves, leaving holes as though made with shot. In severe cases the leaves turn yellow and the trees are defoliated. This disca.se can he prevented by spraying the trees with Bordeaux mixture at intervals of two weeks from the time the leaves ap])car until .July. Another disease to which the i)lum and cherry are subject is the black knot or plum knot, due to I'liiiiiiiililid Diorhdsa, which appears as a serious j)est only upon sour cherries and upon plums. When mature the black knots are rough wart-like excrescences u2)on the branches. At first they are yellowish in color, but soon become darker, the surfaces having a velvet-like appear- . ance. This soon disappo'ars and the knots grow still darker, in winter becoming black. The fun- gus is spread by its spores, which, lighting upon a branch in a crevice in the bark, soon infest the limb. It also remains alive during winter, the mycelium remaining in the twigs anil branches. The infesle<l branches should be cut and burned. and where knots are on large limbs or upon the tree trunks they may be cut out or painted with kerosene. After careful pruning the trees may be sprayed during the growing season with any good fungicide ((|.v. ) to [)revent any spores that may Iind ludgnicnt from germinating. A disease peculiar to the plum is that known as plum pockets, due to attacks of /v'.ioi/.vch.s- iinini. The fruit is infected soon after blossoming and begins to swell until it becomes an inch or two in length. At first the 'pocket' is light in color, but finally becomes dark brown or black, and the fruit falls to the ground. It is usually hollow and bladdery in appearance, hence the name. The walls of the fruit are thickcneil. but it contains no stoni' or jiit. The leaves and stems are also attacked, the atl'ected parts assuming swollen, dis- torted shapes. This disease can be controlled to some extent by thorough use of finigicidcs. Ap- plications should be made before the buds have opened and again just after the flowers have fallen. For an account of plum culture in .meriea and descriptions of the varieties grown, consult: Waugh. riiuits- and Plum Culliire (New York, IflOl): (Joir, Culture of 'Satire PtumK in the 'Xorthircst (Wisconsin Agricultural Experiment Station Bulletins (i.-J and 87); Bailey, The Cul- tii-atrd alire Plums and Cherries (New York. Cornell Experiment Station Bulletin .'58) : id." The Japanese Plums in Ameriea (ib.. Bulletins 62, lOfl, !,■?!». and 17.'5) : Vaugh. The Pollination of Plums and Ih/hrid Plums (Vermont Experi- ment Station Bulletins 53. OT. and 75. and refer- ences for 18!)G-I901). See Colored Plate of Drvpes. PLUM, Bk.vcii (Prunus maritima) . A spi cies (il plum growing upon the Atlantic coast froi New Brunswick to Virginia, and appearing again in Michigan along the lake. As a class beach ]dums are of little value for their fruit, a single named variety only being listcil. Eor ornament, however, the group has greater merit, as the blossoms are rather large and showy and the fruits are of high color when ripe. PLUM, Datk. See Persimmon. PLUMBAGO. Sec Gkapiiite. PLUMBING (from plumb, from OF. plomb, ploni. Fr. plomb, from Lat. plumhum, lead). In its broadest sense, the jiipes and fixtures within houses or other biildings used to sujjply water, gas, and heat, iuehiding in the latter steam and hot water, and also the pipes used to remove liquid wastes from buildings; or the mechanic art of providing the pipes and fixtures niiuicd. A more restricted and more conunon use of the term includes only the water supply and house drainage systems, leaving gas fitting and steam and hot water fitting in two sei)arate classes. (See (iAs, Illuminating; and Heatin(1 anu Ven- TlLATipN.) The (iiirly plumber worked in lead. ))roviding pipe s'stems for water supply, apjily- ing sheet lead for roof coverings and setting window glass. Later lead pipe was adopted for other purposes, notably for gas services, and for removing household wa.stes. Hence the name plumber, originally ajiplied to a worker in lead. Later yet lead was largely replaced by other metals. (See Pii'E.s.) To-day the plumber and the gas, steam, and hot water' titter employ lead, wrought-iron, brass, copper, and the various kinds of plated pipe, including nickel-|dated goods. Vitrified clay or sewer pipe is not used in good phnnbing. at least not in buildings, but vitrified pipe is almost w'holly used to connect the house and street sewerage systems. ^^'ATER Sfppi.Y. The pipe leading from the street main to the building is called the house ll^^^l connection or service pipe and is frequently laid, at least as far as the curb or sidewalk line, by ' the water department. The service pipe, and the water pipe .system within the house as well, may
