ROOT 



ROPES 



801 



the primary and stronger lateral roots, and the 

 subsequent secondary increase in thickness, is a 

 characteristic of gymnosperms and dicotyledons, 

 and does not occur in the cryptogams. This habit 

 often results in the formation of persistent root 

 systems, which in the monocotyledons are often 

 replaced functionally by rhizomes, tubers, and 

 bulbs. 



The stems of the Cycadeae are not unlike those 

 of the Tree-ferns, but unlike them they have tap- 

 roots ; secondary roots appear above ground. In 

 the Coniferae the endosperm bursts the seed-coat at 

 the root end, and the root, which develops a strong 

 tap-root with lateral members, is thrust out. 



The primary root of monocotyledons soon ceases 

 to grow, lateral roots spring from the axis, each 

 new root springs from a point higher up the stem, 

 and being stronger than the older ones, there is 

 no secondary thickening and no persistent root 

 system. Some saprophytic monocotyledons form 

 no roots at all. In dicotyledons an axis below the 

 cotyledons is called the radicle, but the upper and 

 often the larger portion consists of a part of the 

 stem called the hypocotyl ; the lower part is the 

 true embryo root. The root is the tirst part to 

 issue from the burst seed -coat ; it grows and gives 

 rise to lateral roots. If the primary stem grows 

 vigorously the primary root also grows rapidly and 

 forms a tap-root. If the growth ceases adventitious 

 roots are often formed between the former lateral 

 ones, which may themselves give rise to lateral 

 roots. For further information, see Sachs's Physi- 

 ology of Plants (1887) and Goebel's Classification 

 and Morphology of Plants ( 1887 ). 



ROOT-STOCK or Rhizome is the name given to an 

 underground stem when its shape is cylindrical ; to 

 a creeping stem, in short. It is easily distinguished 

 from a root by the fact that it ends in a bud, and 

 bears leaves or scales. It gives off roots every here 

 and there. In the autumn the aerial leaves die 

 down, but the rhizome lives through the winter, 

 and in the spring its terminal bud goes on growing. 

 Rhizomes are usually by the autumn well stored 

 with reserve food-matter for the use of the bud in 

 the following spring. Examples : the anemone, 

 the lily of the valley, the yellow iris, many ferns. 



Root, in Algebra, denotes any value of the 

 unknown quantity in an equation which will 

 render both sides of it identical (see EQUATIONS, 

 INVOLUTION). The square root is that number 

 which, multiplied by itself, produces the given 

 nnml>er ; the cube root, the number which, multi- 

 plied into itself and then into the product, produces 

 the given cube ; so with fourth root, fifth root, &c. 

 The determination of the roots of equations, either 

 formally or actually, constitutes the greater portion 

 of the science of Algebra. 



Root, GEORGE FREDERICK, an American com- 

 poser, was born at Sheffield, Massachusetts, 30th 

 Angnst 1820, taught music in Boston and New 

 York, studied a year in Paris, and returned to 

 write numerous songs that became widely popular. 

 Among them are 'Rosalie, the Prairie Flower,' 

 'There's Music in the Air,' and, during the civil 

 war, ' The Battle-cry of Freedom,' ' Just before the 

 Battle, Mother,' and ' Tramp, tramp, tramp, the 

 Boys are marching." His greater efforts, including 

 a Te Denm, are less known. He died on the 6th 

 of August 1895. 



Root and Branch Men, a party in the 

 Commons and out of it who supported a petition 

 signed by 15,000 London citizens, praying that 

 episcopacy might be destroyed 'root and branch.' 

 Nathaniel Fiennes, Sir Harry Vane, and Hampden 

 were of the party. A bill to give effect to the 

 petition was read a first and a second time in 1641, 

 bat was ultimately dropped. 

 415 



Root-parasites, plants which grow upon, and 

 derive their nourishment from, the roots of other 

 plants. Such are the Broom -rapes ( Orobanchese, 

 q.v.), species of Thesium, &c., and the Rafflesias 

 (q.v.), with other Rhizantheaa (q.v.). 



Ropes. The staple fibre for ropes has long 

 been Hemp (q.v.), but since the middle of the 

 19th century several other fibres have come largely 

 into use. Hemp is better suited for cordage (the 

 general term for ropes, cords, and twine of all 

 kinds) than for weaving purposes, because it 

 gives way when much folded into sharp folds 

 more readily than other important textile fibres 

 flax, for example. Manilla hemp (Musa tex- 

 tilis ; see ABACA), belonging to a quite different 

 order of plants from the common hemp, makes the 

 strongest ropes now manufactured, and is largely 

 employed. Coir fibre, from the husk of the cocoa- 

 nut, is another important rope-making material 

 which, though long used in India, has in Europe 

 only taken its place as a valuable cordage fibre in 

 comparatively recent years. It is fairly strong, 

 and, size for size, it has the advantage of being 

 considerably lighter than either hemp or manilla. 

 Unlike these, coir rope is never tarred for preserva- 

 tion. Sisal hemp, from the Agave sisalana of South 

 America, though not nearly so strong as common 

 hemp, is also much used, especially for ropes of 

 small size. For certain purposes, such as driving 

 parts of textile machinery, cotton ropes are largely 

 employed. There are only two other rope fibres 

 which as yet can be said to be of any import- 

 ance in Britain viz. the Sunn hemp (Crotalaria 

 jtincea ) of India and the Phormium tenax of New 

 Zealand. A large number of plants valuable for 

 cordage grow in India, for a list of which, as well 

 as for an account of the native process of rope- 

 spinning, see Balfour's Cyclopedia of India. 



As regards the strength of ropes, it will be readily 

 understood that in this respect specimens of the 

 same kind of vegetable fibre will vary considerably. 

 Healthy plants will yield a better fibre than those 

 of more feeble growth, and some supplies of the 

 same kind of material will have been more care- 

 fully prepared for spinning than others. The 

 amount of care and skill bestowed upon the spin- 

 ning process itself will also vary in the case of 

 different manufacturers. Tarred ropes, again, 

 though more durable, are not so strong as when left 

 nntarred ; and as tar is liable to be impure it will 

 happen that it weakens or injures the fibre more 

 at one time than at another. These matters will 

 partially explain why an unexpected difference not 

 unfrequently occurs in the strength of two similar 

 ropes which might be supposed to be equally 

 strong. In the valuable work by W. G. Kirkaldy 

 on his father's System of Mechanical Testing ( 1891 ) 

 he gives the breaking stress of a large number of 

 tested ropes, and in his remarks on this section of 

 his experiments points out that the strength of 

 some of these is much lower than it ought to be. 

 He thinks that this can only be accounted for by 

 adulteration of the fibre. It is probable that jute 

 is sometimes mixed with better material. In one 

 instance he found some rubbish called ' batch ' hidden 

 inside the rope. The following examples will show 

 approximately the comparative strength of ropes 

 made of three different materials. They are taken 

 from a table in Mr Kirkaldy's work giving the 

 results of the testing of seventy specimens of ropes. 



Circumference. 



Common hemp, untarred 2'66 in. 



Hemp, tarred 289 u 



Manilla 2'62 u 



Cotton 2-48 u 



Breaking or 



Ultimate Stress. 



4840 Ib. 



4263 i. 



7044 n 



In these instances the strength of the untarred 

 hemp rope is below and that of the manilla rope 



