Heat of the liquid; height of capillary ascent.
Capillary bleeding is a general oozing from a raw surface.
Wide, the water from the pathways is soaked up on each side by capillary attraction, and in this way the roots secure a sufficient supply.
In dry weather, since it promotes capillary action by reducing the soil spaces.
The vessel is completely filled with mercury, the capillary sealed, and the vessel weighed.
He published many physical memoirs on electricity, the dilatation of liquids by heat, specific heats, capillary attraction, atomic volumes &c. as well as a treatise in 4 volumes on Fisica di corpi ponderabili (1837-1841).
Mile of Warsaw in 1828, who termed it a "hydrostatic air-pump without cylinders, taps, lids or stoppers," this is attained by using, both for the inlet and the outlet, vertical capillary glass tubes, soldered, the former to somewhere near the bottom, the latter to the top of the vessel.
The vessel is filled by placing the capillary in a vessel containing the liquid and 6 gently aspirating.
From the bottom there leads P another fine tube, bent upwards, and then at right angles so as to be at the same level as the capillary branch.
In the breeding season the male deposits drops of sperm on a sheet of webbing, picks it up in these flasks by means of capillary attraction and carries it about until he falls in with a female.
In some species (Spengelidae) there is a long capillary vermiform extension of the stomochord in front.
According to Rogowicz and Heidenhain, certain substances increase the quantity of lymph given off from a part by acting upon the cells of the capillary wall; they hold, in fact, that these substances are true lymphagogues.
The point of the rostrum is pressed against the surface to be pierced; then the stylets come into play and the fluid food is believed to pass into the mouth by capillary attraction.
Experiments by the capillary tube method have shown that the viscosity varies more nearly as 0 1, but indicate that the rate of increase diminishes at high temperatures.
P, Osmotic or capillary pressure.
This reflection is suggested by the following articles: Aether; Molecule; Capillary Action; Diffusion; Radiation, Theory Of; and others.
The simplest assumption which suffices to express the small deviations of gases and vapours from the ideal state at moderate pressures is that the coefficient a in the expression for the capillary pressure varies inversely as some power of the absolute temperature.
It consists of a cylindrical tube of a capacity ranging from 10 to 50 cc., provided at the upper end with a thick-walled capillary bent as shown on the left of the figure.
The liquid is adjusted to the mark by withdrawing any excess from the capillary end by a strip of bibulous paper or by a capillary tube.
Acting on a principle quite different from any previously discussed is the capillary hydrometer or staktometer of Brewster, which is based upon the difference in the surface tension and density of pure water, and of mixtures of alcohol and water in varying proportions.
The capillary hydrometer consists simply of a small pipette with a bulb in the middle of the stem, the pipette terminating in a very fine capillary point.
The relation between hydrostatic pressure and the vapour pressure of a pure liquid may be obtained at once by considering the rise of liquid in a capillary tube.
The larger trunks open into each other either directly by cross branches, or a capillary system is formed.
In the smaller and simpler forms the capillary networks are much reduced, but the dorsal and ventral vessels are usually present.
The products obtained by the distillation of petroleum are not in a marketable condition, but require chemical treatment to remove acid and other bodies which impart a dark colour as well as an unpleasant odour to the liquid, and in the case of lamp-oils, reduce the power of rising in the wick by capillary attraction.
Ulrich Kreusler generates the carbon dioxide in a separate apparatus, and in this case the tube is drawn out to a capillary at the end (a).
Capillarity and Surface Tension.-Reference should be made to the article Capillary Action for the general discussion of this phenomenon of liquids.
The apparatus devised by Ramsay and Shields consisted of a capillary tube, on one end of which was blown a bulb provided with a minute hole.
The capillary tube can be raised or lowered at will by running a magnet outside the tube, and the heights of the columns are measured by a cathetometer or micrometer microscope.
De Phys., Paris, 1900, p. 561) that the true effect of magnetization is liable to be disguised by secondary or parasitic phenomena, arising chiefly from polarization of the electrodes and from local variations in the concentration and magnetic condition of the electrolyte; these may be avoided by working with weak solutions, exposing only a small surface in a non-polar region of the metal, and substituting a capillary electrometer for the galvanometer generally used.
The secreting cells never show this change, although they may become atrophied or destroyed by the pressure and the disturbance of nutrition brought about by the swollen condition of the capillary walls.
Heidenhain, on the other hand, rejected entirely the filtration view of lymph-formation, believing that the passage of lymph across the capillary wall is a true secretion brought about by the secretory function of the endothelial plates.
Thus, while increased pressure in the blood or lymph vessels may be one factor, and increased permeability of the capillary endothelium another, increased osmotic pressure in the tissues and lymph is probably the most important in the production of dropsy.
4), consists of a vertical capillary Pump. glass tube a of about 1 mm.
The space between the parts of such substances is too large to admit of capillary action; hence the water conveyed to the surface of the soil is prevented from passing upwards any further except by slow evaporation through the mulching layer.
To prevent this various implements, such as disk harrows and specially constructed rollers, may be used to consolidate the upper stirred portion of the soil and place it in close capillary relationship with the lower unmoved layer.
P. 211, Paris, 1869) proposed an equation of the form (p+po)(v - b) =RO, in which the effect of the size of the molecules is represented by subtracting a quantity b, the " covolume," from the volume occupied by the gas, and the effect of the mutual attractions of the molecules is represented by adding a quantity po, the internal pressure, to the external pressure, p. This type of equation, was more fully worked out by van der Waals, who identified the internal pressure, po, with the capillary pressure of Laplace, and assumed that it varied directly as the square of the density, and could be written a/v 2 .
Solids may be directly admitted to the tube from a weighing bottle, while liquids are conveniently introduced by means of small stoppered bottles, or, in the case of exceptionally volatile liquids, by means of a bulb blown on a piece of thin capillary tube, the tube being sealed during the weighing operation, and the capillary broken just before transference to the apparatus.
Sammetblende or przibramite is a variety, from Przibram in Bohemia, consisting of delicate acicular or capillary crystals arranged in radiating groups with a velvety surface and yellow colour.
The setae are either entirely capillary or there are in addition some sigmoid setae even with bifid free extremities.
On the other hand, it is commonly thought that the single potentialdifferences at the surface of metals and electrolytes have been determined by methods based on the use of the capillary electrometer and on others depending on what is called a dropping electrode, that is, mercury dropping rapidly into an electrolyte and forming a cell with the mercury at rest in the bottom of the vessel.
Laplace was, moreover, the first to offer a complete analysis of capillary action based upon a definite hypothesis - that of forces "sensible only at insensible distances"; and he made strenuous but unsuccessful efforts to explain the phenomena of light on an identical principle.
It was a favourite idea of his that chemical affinity and capillary attraction would eventually be included under the same law, and it was perhaps because of its recalcitrance to this cherished generalization that the undulatory theory of light was distasteful to him.
Dittmar showed that this may be avoided by leading a fine, steady stream of dry gas - air, carbon dioxide, hydrogen, &c., according to the substance operated upon - through the liquid by means of a fine capillary tube, the lower end of which reaches to nearly the bottom of the flask.
4, which has a capacity of about 35 cc., provided with a capillary tube at the top, and a bent tube about 6 mm.
It is necessary to determine the pressure exerted on the vapour by the mercury in the narrow limb; this is effected by opening the capillary and inclining the tube until the mercury just reaches the top of the narrow tube; the difference between FIG.
Algae of more delicate texture than either Fucaceae or Laminariaceae also occur in the region exposed by the ebb of the tide, but these secure their exemption from desiccation either by retaining water in their meshes by capillary attraction, as in the case of Pilayella, or by growing among the tangles of the larger Fucaceae, as in the case of Polysiphonia fastigiate, or by growing in dense masses on rocks, as in the case of Laurencia pinnatifida.
They supposed that it was accompanied by a peculiar hyaline thickening of the arterial wall, usually of the tunica intima, and hence they termed the supposed diseased state " arterio-capillary fibrosis," and gave the fibrous substance the name " hyaline-fibroid."
While this capillary movement of water is of great importance in supplying the needs of plants it has its disadvantages, since water may be transferred to the surface of the soil, where it evapo rates into the air and is lost to the land or the crop growing upon it..
Above the level of the ground-water the soil is kept moist by capillary attraction and by evaporation of the water below, by rainfall, and by movements of the ground-water; on the other hand, the upper layers are constantly losing moisture by evaporation from the surface and through vegetation.
The amount of moisture retained depends mainly upon the absorbability of the soil, and as it depends largely on capillary action it varies with the coarseness or fineness of the pores of the soil, being greater for soils which consist of fine particles.
These are hollow glass beads of variable density; they may be prepared by melting off pieces of very thin capillary tubing, and determining the density in each case by the method just previously described.
If material systems are constituted of discrete atoms, separated from each other by many times the diameter of any of them, this simple plan of exhibiting their interactions in terms of direct forces between them would indeed be exact enough to apply to a wide range of questions, provided we could be certain that the laws of the forces depended only on the positions and not also on the motions of the atoms. The most important example of its successful application has been the theory of capillary action elaborated by P. S.
If a thickwalled capillary tube is passed over the platinum tube and its length so adjusted that the liquid rises in it by capillary action just above the level of the tube, the spectrum may be examined directly, and the loss of light due to the passage through the partially wetted surface of the walls of the tube is avoided.
By this capillary action water may be transferred to the upper layers of the soil from a depth of several feet below the surface.
The honeycomb of rock, and capillary action, retard the lighter fresh-water from sinking to the sea; the soakage from rain has therefore to move horizontally, over the strata about sea-level, seeking outlets.