Henley's pith ball electrometer (Phil.
The secondary phloem contains numerous thick-walled fibres, parenchymatous cells, and large sieve-tubes with plates on the radial walls; swollen parenchymatous cells containing crystals are commonly met with in the cortex, pith and medullary-ray tissues.
The sudden termination of the secondary tracheids against the pith-cells may afford evidence of root-structure as distinct from stem-structure, in which the radial rows of secondary tracheids pass into the irregularly-arranged primary elements next the pith.
It is here, at the Heribert present epoch and for the next two centuries, that the and the pith and nerve of the Italian nation must be sought; Lombard and among the burghs of Lombardy, Milan, the eldest burghs.
In others a central parenchyma or primetive pith a new region of the primitive stelar conjunctiveappears in the centre of the xylem.
In the majority of ferns, at a higher level, after the stele has increased greatly in diameter, a large-celled true pith or medulla, resembling the cortex in its characters, and quite distinct from conjunctive, from which it is separated by an internal endodernlis, appears in the centre.
The centre of the S~hooo- stele is however often occupied by a large-celled pith resembling the cortex in structure, the cortex and pith ~ together being classed as ground tissue.
To this type of steIn having a ground-tissue pith, whether with or without internal phloem, is given the name siphonostele to distinguish it from the solid haplostele characteristic of the root, the first-formed portion of the stem, and in the more primitive Pteridophytes, of the whole of the axis.
When the pith is large celled, the xylems of the bundles are separated from it by a distinct layer of conjunctive tissue called the endocycle, and a similar layer, the pericycle, separates the phloem from the cortex.
The arrangement of the conducting tissue in the stem is characteristic; a transverse section of the very young stem shows a nunber of distinct conducting strands - vascular bundles - arranged in a ring round the pith; these soon become united to form a closed ring of bast and wood, separated by a layer of formative tissue (cambium).
As the diplomatic crisis approached, spies were sent into Prussia, and simultaneously with the orders for preliminary concentration the marshals received private instructions, the pith of which cannot be better expressed than in the following two quotations from Napoleon's correspondence: " Mon intention est de concentrer toutes mes forces sur l'extremite de ma droite en laissant tout l'espace entre le Rhin et Bamberg entierement degarni, de maniere a avoir pres de 200,000 hommes reunis sur un meme champ de bataille; mes premieres marches menacent le coeur de la monarchie prussienne " (No.
ï¿½, and (alai +(72a2+a3a3+ï¿½ï¿½ ï¿½) P = (Pith +P2t2 +P3f 3 3+ ï¿½ ï¿½ ï¿½) P ï¿½ Instead of the above symbols we may use equivalent differential operators.
The fruit is edible and its juice is made into beer; the sap of the tree is made into wine, and its pith into bread; the leaves furnish an excellent thatch, and the fibre extracted from their midribs is used f or fish lines, cordage, hammocks, nets, &c.; and the wood is hard and makes good building' material.
If a suspended gilt pith ball is held near it, the ball will first be attracted and then repelled.
He held that the people, as distinguished from the nobles and the clergy, were the pith and fibre of nations; yet this same people had to become wax in the hands of the politician - their commerce and their comforts, the arts which give a dignity to life and the pleasures which make life liveable, neglected - their very liberty subordinated to the one tyrannical conception.
The primary vascular bundles in a young conifer stem are collateral, and, like those of a Dicotyledon, they are arranged in a circle round a central pith and enclosed by a common endodermis.
Its pith was also a common article of food, and was eaten both cooked and in its natural state.
In addition to these cauline (fi rstcell).(After strands (confined to the stem and not connected Webber.) with the leaves), collateral bundles are often met with in the pith, which form the vascular supply of terminal flowers borne at intervals on the apex of the stem.
Secretory sacs occur abundantly in the leaflamina, where they appear as short lines between the veins; they are abundant also in the cortex and pith of the shoot, in the fleshy integument of the ovule, and elsewhere.
The tree which supplies the materials for the pith paper of the Chinese is not uncommon, and the cassia tree is found in the mountains.
The pith is in the centre of the tree and around it the wood is disposed in approximately concentric rings; that part near the pith is hard and close in grain, and from its position is termed heart-wood.
The pith is encircled by a cylinder of secondary wood, consisting of single or multiple radial rows of tracheids separated by broad medullary rays composed of large parenchymatous cells; the tracheids bear numerous bordered FIG.
p. sclerised pith; c. cainbium; p.m.r.
They usually run freely in the pith and Polycycly.
The conjunctive of a root-stele possessing a pith is often sclerized between the pith and the pericycle.
The old idea that it was made from layers or pellicules growing between the rind and a central stalk has been abandoned, as it has been proved that the plant, like other reeds, contains only a cellular pith within the rind.
(Cacoecia gallicolens), of the family Drepanulidae, causes the stem of a creeping plant, on the pith of which it apparently subsists, to swell up into a fusiform gall.'
A double pith ball repulsion electrometer was employed by T.
Besides these we have in the same period the spark telegraph of Reiser, of Don Silva, and of Cavallo, the pith ball telegraph of Francis Ronalds (a model of which is in the collection of telegraph apparatus in the Victoria and Albert Museum), and several others.
In some cases this individualization is carried ftirther, the cortex and pith becoming continuous between the bundles which appear as isolated strands em- Aberrant bedded in a general \, L.~/ ~ Typesof ground-tissue.
The young tissue of the stelar cylinder, in the case of the modified siphonostele characteristic of the dicotyledonous stem, differs from the adjoining pith and cortex in its narrow elongated cells, a difference produced by the stopping of transverse and the increased frequency of longitudinal divisions.
Then take two suspended gilt pith balls and touch them (a) both against one tray; they will be found to repel each other; (b) touch one against one tray and the other against the other tray, and they will be found to attract each other.
The wood of the fly honeysuckle is extremely hard, and the clear portions between the joints of the stems, when their pith has been removed, were stated by Linnaeus to be utilized in Sweden for making tobacco-pipes.
In the larger of the two great groups into which the Angiosperms are divided, the Dicotyledons, the bundles in the very young stem are arranged in an open ring, separating a central pith from an outer cortex.
A transverse section of a tree of this class shows it to consist of three distinct parts: the pith or medulla, the wood, made up of annual rings or layers, and the bark.
It is supposed to be caused in severe weather by the freezing of the ascending sap. "Heart shake" is often found in old trees and extends from the pith or heart of the tree towards the circumference.
Dwellings require careful construction, with thick walls and roofs of non-conducting material to keep out the heat-rays, and fans and punkahs are essential for the promotion of currents of air in the inhabited rooms. Personal protection, in the shape of thick pith topees, or cork helmets, and spinal pads, is necessary in the hot months, the clothing being light and loose and not too thin.
The younger generation adopted a round pith hat with a rolled edge of felt, but, under the influence of the swadeshi movement, they have generally reverted to the older form (Plate I.
The object of the thimbleshaped dome was to keep moisture from the stem from which the pith balls were supported, so that the apparatus could be used in the open air even in the rainy weather.
Let two spherical pith balls of radius r and weight W, covered with gold-leaf so as to be conducting, be suspended by parallel silk threads of length 1 so as just to touch each other.
A bunch of ' tang sani ' (lamp-wick, the pith of Eriocaulon or Scirpus) is then inserted well into the mass, and the pan slightly canted, when a rich, clear, brown fluid is thus drawn off, and filtered through ' chi mui ' (paper made from bamboo fibre).
The type of siphonostele characteristic of many ferns, in which are found internal phloem, and an internal endodermis separating the vascular conjunctive from the pith is known as a solenostele.
endoderruis; p.c. passage ylem; p. pith; ccl.
Where a large-celled pith is developed this often becomes obvious very early, and in some cases it appears to have separate initials situated below those of the hollow vascular cylinder.
In some cases where there is apparently a well-marked plerome at the apex, this is really the young pith, the distinction between the stelar and cortical initials, if it exists, being, as is so often the case, impossible to make out.
The accuracy of his measurement, by which he established within 2% the above law, was only limited by the sensibility, or rather insensibility, of the pith ball electrometer, which was his only means of detecting the electric charge.2 In the accuracy of his quantitative measurements and the range of his researches and his combination of mathematical and physical knowledge, Cavendish may not inaptly be described as the Kelvin of the 18th century.
Sometimes a complete internal vascular cylinder, having the same structure as the primary one, and concentric with it, occurs in the pith, and others may appear, internal to the first (Matonia, Saccoloma).
When the diameter of the stele is greater, parenchymatous conjunctive tissue often occupies its centre and is frequently called the pith.
In some forms other gaps (perforations) appear in the vascular tube placing the pith and cortex in communication.
It consists of a ring of endarch collateral bundles1 surrounding a hollow pith.
The whole stele may be surrounded by a common external endodermis; sometimes there is an internal endodermis in addition, separating the bundles from the pith; while in other cases each bundle possesses a separate endodermis surrounding it.
The typical structure of the vascular cylinder of the adult primary stem in the Gyrnnosperms and Dicotyledons is, like that of the higher ferns, a hollow cylinder of vas- Structure of cular tissue enclosing a central parenchymatous pith.
In the stems of many water-plants various stages of reduction of the vascular system, especially of the xylem, are met with, and very often this reduction leads to the formation of a compact stele in which the individuality of the separate Reduced bundles may be suppressed, so that a closed cylinder lmpbost~h1c of xylem surrounds a pith.
Though the city has specialities of jewelry, carpets, modelling in pith, &c., there are no large industries.
In medieval and modern Greek, however, this has become the unvoiced sound represented in English by th in thin, thick, pith.
One form of Cephalotaxus is characterized by the presence of short tracheids in the pith, in shape like ordinary parenchyma, but in the possession of bordered pits and lignified walls agreeing with ordinary xylem-tracheids; it is probable that these short tracheids serve as reservoirs for storing rather than for conducting water.
On the eastern plains are to be found the "miriti" (Mauritia flexuosa) and the "pirijao" or peach palm (Guilielma speciosa), called the "pupunha" on the Amazon, whose fruit, fibre, leaf, sap, pith and wood meet so large a part of the primary needs of the aborigines.
The stem is monostelic, the vascular tissues being separated into curved groups comparable with collateral vascular bundles, which surround the pith.
Her love for Kiartan the poet, and his career abroad, his betrayal by his friend Bolli, the sad death of Kiartan at his hands, the revenge taken for him on Bolli, whose slayers are themselves afterwards put to death, and the end of Gudrun, who becomes an anchorite after her stormy life, make up the pith of the story.
It deals especially with law, and contains the pith and the moral of all early Icelandic history.
In British New Guinea alone is the mancatcher (a rattan loop at the end of a handle with a pith spike projecting into it) met with.
In many cases internal casts have been formed, some large cavity, such as a fistular pith, having become filled with mineral substance, which has taken the impress of the surrounding structures, such as the wood.
Part of transverse section of a young stem, showing pith, vascular bundles with secondary wood, and cortex.
Transverse section of stem, showing the pith containing groups of sclerotic cells, the primary xylem-strands, secondary wood and phloem, pericycle and cortex.
They are of similar structure in all known Calamarieae, the main roots having a large pith, while the rootlets had little or none.
The stem is traversed by a single stele, with solid wood, without pith; the primary xylem is triangular in section, the spiral elements forming one or two groups at each angle, while the phloem occupied the bays, so that the structure resembles that of a triarch root.
In the larger stems of most species there was a central pith, but in certain of the smaller branches, and throughout the stem in some species (L.
p, Pith, almost destroyed.
The two parts are very different in structure: in the main axis, as shown in the common Coal Measure form Stigmaria ficoides, the centre was occupied by the pith, which was surrounded by a zone of wood, centrifugally developed throughout.
The stem has a single stele, resembling in general primary structure that of one of the simpler species of Gleichenia; there is no pith, the wood extending to the centre of the stele.
Coal Measures, is now the best-known of all Palaeozoic plants, the central wood has disappeared altogether and is replaced by pith; the primary wood is only represented in the leaf-trace strands, which form a ring of distinct collateral bundles around the pith; (From a model after Oliver.) FIG.
A few Coal Measure and Permian stems (Cycadoxylon and Ptychoxylon) resemble Lyginodendron in the general character of their tissues, but show a marked reduction of the primary wood, together with an extensive development of anomalous wood and bast around the pith, a peculiarity which appears as an individual variation in some specimens of Lyginodendron oldhamium.
In many Cordaiteae the pith was discoid, i.e.
In those stems which have been referred with certainty to the Cordaiteae there is no centripetal wood; the spiral elements are adjacent to the pith, as in a recent Conifer or Cycad; certain stems, however, are known which connect this type of structure with that of the Lyginodendreae; this, for example, is the case in the Permian genus Poroxylon, investigated by Bertrand and Renault, which in general structure has much in common with Cordaiteae, but possesses strands of primary wood, mainly centripetal, at the (After Grand' Eury, modified.
boundary of the pith, as in the case in Lyginodendron.
The stem resembled that of Cycads in having a large pith, sometimes as much as 4 in.
13, B) a large pith is seen to occupy the axial region, and this is surrounded by a zone of secondary wood, which appears to differ from the characteristic wood of modern Cycads (see Gymnosperms) in having a more compact structure.
i, Bennettites stem: portion of transverse section of stem; a, vascular cylinder; b, leaf-traces; c, pith; d, cortex.
hold grapefruit over bowl and cut away skin, along with pith, to reveal juicy ruby flesh.
Showing two men in pith helmets seated in the shade of some trees.
pith necrosis symptoms developed on inoculated plants in 7 days. No symptoms developed on negative control plants.
The section shows from the pith (at right) to the cortical parenchyma (at left ).
Zest and juice the lemon, discarding the pith and seeds.
Pretty dirty things Caroline Boucher gets a handle on heavy-duty pots and pans and a powerful juicer that really takes the pith.
Sambar antler is strong and heavy, having very little pith, and can be worked more extensively than most others.
Quarter the peppers, remove the stem and white pith and lay them skin side upwards on a foil lined grill pan.
If using the zest, scrub the skin thoroughly and avoid cutting or grating too deeply - the bitter white pith is best avoided.
The soft pith from inside the tough stems was cut into long strips.
Cut the red peppers in half, cut out the central white pith and seeds, chop the peppers into smallish pieces.
elder pith could be hollowed out to leave a tube suitable for the making of a toy gun.
pith helmets seated in the shade of some trees.
pith balls and a Van de Graaf generator help to illustrate the principles presented.
pith of a Chinese tree.
pith of the papyrus plant, which then grew plentifully in the Nile.
pith from the grapefruit.
pith from the red pepper and slice into 4 pieces.
pith from the remaining orange and slice the flesh.
cut the red peppers in half, cut out the central white pith and seeds, chop the peppers into smallish pieces.
red peppers in half, cut out the central white pith and seeds, chop the peppers into smallish pieces.
Where cut surfaces reveal the pith, they need to be capped off with wood, horn or synthetic resin.
Le Sage proposed a similar method, in which each conductor was to be attached to a pith ball electroscope.
In most ferns internal p/deem appears instead of a ~arenchymatous pith (fig.
The solenostele of the ferns is broken by the departure of each leaf-bundle, the outer and inner endodermis joining so that the stele becomes horseshoe-shaped and the cortex continuous with the pith (fig.
The main events in this transition appear to have been (I) disappearance of the central xylem of the protostele and replacement by pith, leading to the survival of a number of (mesarch) collateral bundles (see below) at the periphery of the stele; (2) passage from mesarchy to endarchy of these bundles correlated with a great increase in secondary thickening of the stele.
The external conjunctive tissue is often arranged in relation to each bundle separately, the pericyclic fibres for instance, already referred to, being cften confined to the bands of pericyclic tissue abutting on the phloem of each bundle, while the Cortex and pith frequently form rays in the intervals between the adjacent bundles.
While the stele of the primary root in both Gymnosperms and Angiosperms is usually diarch or tetrarch, the large primary root-steles of many adventitious roots are frequently polyarch, sometimes with a very large number of protoxylems. Such a stale seldom has the centre filled up with xylem, this being replaced by a large-celled pith, so that a siphonostelic structure is acquired (fig.
Many larvae of beetles, moths, &c., bore into bark, and injure the cambium, or even the wood and pith; in addition to direct injury, the interference with the transpiration current and the access of other parasites through the wounds are also to be feared in proportion to the numbers of insects at work.
The injured cells die and turn brown; the living cells beneath grow out, and form cork, and under the released pressure bulge outwards and repeatedly divide, forming a mass Of succulent regenerative tissue known as callus, Living cells of the pith, phloem, cortex, &c., may also co-operate in this formation of regenerative tissue, and if the wound is a mere knife-cut in the bark, the protruding lips of callus formed at the edges of the wound soon meet, and the slit is healed overoccluded.
Ã¯¿½, and (alai +(72a2+a3a3+Ã¯¿½Ã¯¿½ Ã¯¿½) P = (Pith +P2t2 +P3f 3 3+ Ã¯¿½ Ã¯¿½ Ã¯¿½) P Ã¯¿½ Instead of the above symbols we may use equivalent differential operators.
For this purpose the following apparatus should be provided: - (i) two small metal tea-trays and some clean dry tumblers, the latter preferably varnished with shellac varnish made with alcohol free from water; (2) two sheets of ebonite rather larger than the tea-trays; (3) a rod of sealing-wax or ebonite and a glass tube, also some pieces of silk and flannel; (4) a few small gilt pith balls suspended by dry silk threads; (5) a gold-leaf electroscope, and, if possible, a simple form of quadrant electrometer (see Electroscope and Electrometer); (6) some brass balls mounted on the ends of ebonite penholders, and a few tin canisters.
Henley and others devised the pith ball, or double straw electroscope (fig.
Cavallo about 1770 employed two fine silver wires terminating in pith balls suspended in a glass vessel having strips of tin-foil pasted down the sides (fig.
Trans., 1 77 2, 6 3, p. 359) in which the repulsion of a straw ending in a pith ball from a fixed stem is indicated on a graduated arc (see Electroscope).
a, The main anatomical features of a cycad stern a Spermatozoids may be summarized as follows: the centre is from G of fi occupied by a large parenchymatous pith traversed g; by numerous secretory canals, and in some genera c p onen-grain by cauline vascular bundles (e.g.
Cephalotaxus (Taxeae) is also peculiar in having resincanals in the pith (cf.
The usually fistular pith is surrounded by a ring of collateral vascular bundle, (see Anatomy Of Plants, and Pteridophyta), each of which, with rare exceptions, has an intercellular canal at its inner edge, containing the disorganized spiral tracheae, just as in the recent genus.
Figure 1: Brown water-soaked and dry pith necrosis of the stem of tomato seedling inoculated with Pseudomonas mediterranea.
A view showing two Europeans in pith helmets standing in a field of growing sisal plants.
The larva always feeds singly on the pith in the cavity of a teasel seedhead.
Using a sharp peeler, grater or knife, remove the yellow rinds, and take care to separate it from the white pith beneath it.
Peel the lemon, being sure to remove all the pith (white part).
Instead, use the white part of an orange rind (the pith) and rub it against your teeth.
The natural chemical in the pith of an orange will whiten your teeth rather effectively.
Remove the pith from the peels and the fruits.
The word usage examples above have been gathered from various sources to reflect current and historial usage. They do not represent the opinions of YourDictionary.com.