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.
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.
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.
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.
In some forms other gaps (perforations) appear in the vascular tube placing the pith and cortex in communication.
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 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.
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 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.
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.
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.
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).
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.
Its pith was also a common article of food, and was eaten both cooked and in its natural state.
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.
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.
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.
If a suspended gilt pith ball is held near it, the ball will first be attracted and then repelled.
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.
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.
(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.'
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.
The hair covering the body is long, coarse, and of a peculiarly brittle and pith-like character, breaking easily; it is generally of a greyish-brown colour, sometimes inclined to yellowish-red, and often variegated with lighter patches.
The hyphae will also dissolve their way through a lamella of collodion, paraffin, parchment paper, elder-pith, or even cork or the wing of a fly, to do which it must excrete very different enzymes.
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.
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.
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.
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.
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.
Henley's pith ball electrometer (Phil.
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 double pith ball repulsion electrometer was employed by T.
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).
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.
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.
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.
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 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.