Working fluid

“ All that is necessary to complete the successful operation of the system is to have additional stations at which the moving fluid can obtain supplies of food materials and of oxygen, and stations where it can get rid of the wastes which it accumulates from the stationary fluid, and there must be a pump by which the moving fluid is kept in motion. ”

“ He watched as the fluid he had poured emerged into glass tubing no thicker than a human hair, and, under the tons per square inch pressure, stretched into fine fluid columns less than half a dozen molecules thick. ”

“ Under the pressure in these minute vessels, fluid matter oozes through their walls and bathes all the neighbouring tissues. This fluid holds in solution the matters needed for nourishing the tissues, and it also contains gases in solution. Thus the fluid is both a nutritive and respiratory medium; by it the tissues are nourished, and by it they breathe. ”

“ To this if we add a Pression of the several Parts of the Fluid every way, and consider withal, that this Uniform Attraction of the Parts to one another must be variously changed by the different Attraction of Heterogeneous Bodies mixt with them, we have the great Principles of all Fluids, upon which their several Phænomena do depend.
And hence it follows, that whatsoever Power is sufficient to make a Change in this Attraction, or Cohæsion of the Parts, makes an Alteration of the Nature of the Fluid; that is, as the Chymists express it, puts it into a Fermentation. ”

“ For this it will be necessary to consider the variations of the energy of the fluids only so far as they are immediately connected with the changes in the solid. We may suppose the solid with so much of the fluid as is in close proximity to it to be enclosed in a fixed envelop, which is impermeable to matter and to heat, and to which the solid is firmly attached wherever they meet. ”

“ EXPRES′SION. In the useful arts, the mechanical operation by which a fluid contained in the pores or cells of a solid is pressed out or expelled. Many of the fluid substances employed in pharmacy and chemistry are obtained682 by expression. Thus, the unctuous vegetable oils, as those of almonds, linseed, &c., are procured by submitting these substances to powerful pressure between iron plates, which are either made warm, or the bruised seeds are previously exposed in bags to the steam of boiling water. The juices of fresh vegetables are also obtained by expression. ”

“ In proportion as digestion and absorption of food become specialized and restricted to certain parts, circulation becomes more important in order to convey that food to the tissues, and carry from the tissues the worn-out material. To maintain the character of the fluid, it must itself undergo constant change, and hence the excretory processes—respiration being the most urgent—which increase the necessity for movement of the fluid. Circulation of the nutritive fluid is the immediate function for upbuilding and repairing the body. ”

“ We will now consider the stability of a fluid enclosed in a rigid envelop which is non-conducting to heat and impermeable to all the components of the fluid. The fluid is supposed initially homogeneous in the sense in which we have before used the word, i.e., uniform in every respect throughout its whole extent. Let be the ultimate components of the fluid; we may then consider every body which can be formed out of the fluid to be composed of , and that in only one way. Let denote the quantities of these substances in any such body, and let , denote its energy, entropy, and volume. ”

“ This fluid may possibly be the same with that which attracted by and entering into other more solid matter, dilates the substance, by separating the constituent particles and so rendering some solids fluid, and maintaining the fluidity of others; of which fluid when our bodies are totally deprived, they are said to be frozen; when they have a proper quantity they are in health, and fit to perform all their functions ”

“ The pores of all bodies are supposed 117to be full of this subtile fluid; and when its equilibrium is not disturbed, that is, when there is neither more nor less of it in a body than its natural share, or than it is capable of retaining by its own attraction, the fluid does not manifest itself to our senses. The action of the rubber upon an electric disturbs this equilibrium, occasioning a redundancy of the fluid in one place, and a deficiency of it in another. This equilibrium being forcibly disturbed, the mutual repulsion of the particles of the fluid is necessarily exerted to restore it. ”

“ With regard to the power which sets bounds to the expansion of the fluid acting as heat, it is natural to think that it can be no other than the same fluid acting in a contrary direction, or from a circumference towards a centre; and thus we shall always find that the same fluid, by limiting its own operations, may produce those phenomena which have been hitherto deemed so difficult of explanation. ”

“ There are three physical states or conditions of matter, which are the solid, liquid and gaseous, which in this connection apply to Ice, Water and Steam. A solid offers resistance both to change of shape and to change of bulk.
A Fluid offers no resistance to change of shape. Again fluids can be divided into liquids and vapors or gases. Water is the most familiar example of a liquid. A liquid can be poured out in drops while a gas or vapor flows in a stream or streams. ”

“ The Science of Hydrostatics depends upon the Fundamental Principle that fluids press equally in all directions. This principle necessarily results from the conception of a Fluid, as a body of which the parts are perfectly moveable in all directions. For since the Fluid is a body, it can transmit pressure; and the transmitted pressure is equal to the original pressure, in virtue of the Axiom that Reaction is equal to Action. That the Fundamental Principle is not derived from experience, is plain both from its evidence and from its history. ”

“ To the questions,—What are the forces by which absorption, secretion, and the vital motions, of fluids are produced?—no satisfactory answer has been returned. Yet still some steps have been made, which it may be instructive to point out.
12. In Absorption it would appear that a part of the agency is inorganic; for not only dead membranes, but inorganic substances, absorb fluids, and even absorb them with elective forces, according to the ingredients, of the fluid. A force which is of this kind, and which has been termed Endosmose, has been found to produce very curious effects. ”

“ If either of the elements of common air should be found to be capable of reduction to a liquid state before it unites into a corrosive fluid with the other ingredient, then we shall possess a ready means of conveying power in any quantity and to any distance. ”

“ Men’s bodies are [Pg 145] pneumatic-hydraulic machines, composed of fluid and solid materials, and health depends on the fluids being prevented from coagulating, by being stirred up by the constant operations of the currents of air which penetrate the frame through the pores and mouth. The solid portion of the body is disposed to harden and dry up and become stiff, and this produces age and decay ”

“ If any obstructing blood or other fluid should be deposited in quantities great enough to stop other fluids from passing on their way, Nature will fire up its engine to remove such deposits by converting fluids into gas. As heat and motion have much to do as remedies, we may expect fever and pain until nature's furnace produces heat, forms and converts its fluids into gas and other deposits, and passes them through the excretories to space, and allows the body to work normally again. ”

“ This law is, that when a vacuum is made in either air or water, the surrounding fluid presses from all sides, and from the bottom as strongly as from above. And thus, when a vacuum is made by the raising of the diaphragm, there is a pressure on all sides of the body, forcing the intestines upward to fill the vacuum thus made. ”

“ This may sometimes, or perhaps generally, make it a necessary condition of equilibrium in cases of contact between a fluid and an amorphous solid which can be formed out of it, that the solid at the surface where it meets the fluid shall be sensibly in a state of hydrostatic stress. ”

“ But, further, in fluids such as water, air, steam, &c., to which the present division of the article relates, the tangential stresses that are called into action between contiguous portions during distortion or change of figure are always small compared with the weight, inertia, pressure, &c., which produce the visible motions it is the object of hydraulics to estimate. On the other hand, while a fluid passes easily from one form to another, it opposes considerable resistance to change of volume. ”

“ In ordinary hydraulics, liquids are treated as absolutely incompressible. In dealing with gases the changes of volume which accompany changes of pressure must be taken into account.
§ 3. Viscous fluids are those in which change of form under a continued stress proceeds gradually and increases indefinitely. A very viscous fluid opposes great resistance to change of form in a short time, and yet may be deformed considerably by a small stress acting for a long period. ”

“ Osmosis takes place when two fluids of different osmotic pressure are separated by animal membrane. Difference in osmotic pressure is due to differences in molecular concentration, the greater the number of molecules the greater is the pressure, and the greater rapidity of flow is from the fluid of less pressure to the fluid of greater pressure. The molecular concentration of tissue and blood fluid is constantly being equalized by the process of osmosis. ”

“ B. Yes; fluids, generally speaking, are bodies of less density than solids. From the slight cohesion, of the particles of fluids, and the facility with which they slide over each other, it is inferred, that they have but a slight attraction for each other, and that this attraction is equal, in every position of their particles, and therefore produces no resistance to a perfect freedom of motion among themselves.
Caroline. Pray what is the distinction between a fluid and a liquid?
Mrs. B. Liquids comprehend only one class of fluids. ”

“ To make room for fluid. The average embalmer only injects a gallon to a gallon and a half of fluid into a body. There are times when the operator desires to use more fluid. It may be that the body will have to be shipped a long distance, perhaps to another country or a distant state. ”

“ Fluid. A form of matter, in which its particles readily flow, or slide, over each other. Airs, or gases, are called elastic fluids, because they are readily reduced to a smaller bulk by pressure. Liquids, are denominated non-elastic fluids, because they suffer but little diminution of bulk, by any mechanical force.
Focus. That point in which converging rays unite.
Force. That power which acts upon a body, either tending to create, or to stop motion.
Fountain. A jet, or stream of water, forced upwards by the weight of other water, by the elasticity of air, or some other mechanical pressure. ”

“ The properties of hydrogen gas compared with those of the denser aëriform fluids will, in some slight degree, aid our conception of the excessive mobility and penetrating activity of a fluid so constituted. ”

“ It will be perceived that the hot fluid enters the apparatus at top, and the cold fluid at bottom, passing each other, by means of which an interchange of temperatures takes place through the plates of copper, the cooling fluid passing off at top in a heated state, by means of the caloric which it has abstracted from the hot fluid; and the hot fluid passing off through the pipe and cock at bottom, in a very reduced state of temperature, by reason of the caloric which it held having been given out to the cooling fluid. ”

“ At each beat a little over two ounces of blood is thrown out of it; and each day it receives and discharges seven tons of that wonderful fluid. Your lungs will contain a gallon of air, and you inhale twenty-three thousand gallons a day. ”

“ In the ordinary circumstances of daily life the amount of fluid which is thus given off from the skin (and lungs) during the twenty-four hours varies from 12⁄3 lb. to 5 lb.; under extraordinary circumstances the amount will, of course, rise enormously. Dr. Southwood Smith found that the workmen in the gasworks employed in making up the fires, and other occupations which subjected them to great heat, lost on an average 3 lb. ”

“ If a fluid be composed of particles mutually flying each other, and the density be as the compression, the centrifugal forces of the particles will be reciprocally proportional to the distances of their centres. And vice versa, particles flying each other with forces that are reciprocally proportional to the distances of their centres, compose an elastic fluid, whose density is as the compression. ”

“ That a Body, immersed in a Fluid, sustains a Lateral pressure from the Fluid; and that increased, as the depth of the immersed Body, beneath the Surface of the Fluid, increaseth.
8. That Water may be made as well to depress a Body lighter than it self, as to buoy it up. ”

“ We may by the method of (28) , when the distribution of pressures is known, construct the surfaces of equal pressure, the tubes of fluid motion, and the sources and sinks. It is evident that since in each cell into which a unit tube is divided by the surfaces of equal pressure unity of fluid passes from pressure to pressure ) in unit of time, unity of work is done by the fluid in each cell in overcoming resistance. ”