Buoyancy device

“ When preparing to ascend the diver must tighten the air valve in his helmet to increase his buoyancy; if the valve is closed too much to allow the excess air to escape, his ascent will at first be gradual, but the pressure of the water reduces, the air in the dress expands, making it so stiff that he cannot move his arms to reach the valve, and he is blown up, with ever-increasing velocity, to the surface. ”

“ This discovery could be made, he went on to say; and upon it depended improvement in aerial travelling. Each fan could be impelled by a separate machine of a light weight, worked with perfect safety by a cheap material; for the probabilities were, the substance would be cheaply producible. Each aerial vessel should carry three or four times the number of separate fans and machinery necessary to obtain buoyancy. The same substances probably could be used to procure buoyancy in the improbable event of all the machines breaking down. ”

“ The envelope being partly filled with coal-gas-heated air and hydrogen, is much lighter than the surrounding atmosphere, and rises to a height according as the density of the air strata diminishes. The density is less as we ascend, and the buoyant force also is lessened in proportion. So when the weight of the balloon and its occupants is the same as the power of buoyancy, it will come to a stand, and go no higher. ”

“ In order to fly in the air, and steer in a given direction during a given period, it is requisite to take up a buoyancy and a power which shall be greater (and continuously so during the voyage) than needful to sustain its own mechanical weight, together with that of the aeronauts and their various appurtenances; and as much also in excess of these requisitions as shall overcome the adverse action of the wind upon the resisting surface presented by the machine. At present no such power is known which can be used in combination with a balloon, or other gas machine. ”

“ If the diver feels bad while under water he should signal for more air, stop moving about, and rest quietly for a minute or two, when the fresh air will revive him. The volume of air required by the diver for respiration is about 1.5 cubic feet per minute, and there is a non-return valve on the air inlet, so that in the event of the air pipe being broken, or the pump failing, the air would not escape backwards, but by closing the outlet valve the diver could retain sufficient air to enable him to reach the surface. ”

“ It is well to have some water in your neighborhood, to give buoyancy to and float the earth. ”

“ This moisture is brought into the tube with the air, and is deposited upon the walls of the tube when their temperature is sufficiently below that of the atmosphere. The atmosphere always contains more or less moisture in the state of vapor. The capacity of air for water-vapor depends upon its temperature, being greater the higher the temperature, but it is a fixed and definite quantity at any given temperature. When the air contains all the water-vapor it can hold at a certain temperature, it is said to be saturated. ”

“ If steam be blown into a large inclined pipe full of water, it will rise by difference of gravity to the top of the pipe, forming a bubble; when condensation takes place, the water below the bubble will rush up to fill the vacuum, giving a blow directly against the side of the pipe. As the water still further recedes the bubble will get larger, and move farther and farther up the pipe, the blow each time increasing in intensity, for the reason that the steam has passed a larger mass of water, which is forced forward by the incoming steam to fill the vacuum. ”

“ In generating steam from cold water all the free air is liberated and driven off into the pipe, with the air left in them, all of which is forced up to the highest point of the coils or radiators, and compressed equal to the steam pressure following it. Now, by placing a valve or vent at the return end of the pieces to be heated, the air will be driven out by the compression. Why the vent is placed at the return is, that the momentum of the steam, it being the lightest body, will pass in the direction of it, falling down into the return as it condenses, thus liberating the air. ”

“ The pneumatic system requires a pump, an air-tight tank, and pipes to the various outlets. The water pumped into the air-tight tank will occupy part of the space generally occupied by the air. The air cannot escape and is, therefore, compressed. ”

“ By having his pump attached to the well tube directly, the working of the pump creates a vacuum, and the atmospheric pressure on the earth's surface violently forces the liquid to fill the vacuum thus formed, thereby giving a much greater amount of water than can be otherwise obtained. It is a well established fact that more water can be obtained by the drive well than by any other. ”

“ It is impossible to retain water in a liquid state, in an open vessel, after it has reached that temperature. If the vessel in which the water is heated, however, be overed, and the cover be fastened down, the water can be heated to any temperature whatever, and will still remain in the liquid state. The tendency of the water to pass into vapor increases with the degree of heat applied to it, and there must, therefore, be a proportionate pressure or restraint by the inclosing vessel on the heated water to overcome this expansive tendency, or tendency to pass into a state of a vapor. ”

“ The great body of water below the flues will therefore only take up heat relatively slowly, and will, on account of its bulk and its physical properties, but slowly lose it. Should the flame fall in power, or even go out for ten or twelve hours, it is claimed that no serious loss of efficiency of the apparatus will result.
Regulation of the temperature is by means of an air tube, the air in which expanding bulges out an india-rubber diaphragm and this moves a lever. The lever operates a valve which allows more or less of the heated air to escape from the egg-drawer. ”

“ Most air lift propositions are deep-well cases—that is, the water is lifted a distance greater than 25 feet; and just in proportion as the lift is increased do we get away from the aerated form idea, and so when the air pressure is greater than the head of water, a certain volume of compressed air is received into the eduction-pipe, the water in this pipe is at that time moving rapidly upward; that is, its momentum has been established. Hence the air takes up this velocity and goes upward with the water from the energy received from the elasticity of the air due to its compressor. ”

“ At the same time the air-supply through these pipes was so improved that the air in the pipes, by mechanical contrivances, was kept at a considerable pressure; and by means of valves and stopcocks, the act of breathing below water is performed as easily as in the atmosphere; and there is no need to come to the surface at all for purposes of respiration. The breathing apparatus is so constructed that every mouthpiece is connected with two sets of tubes, one of which receives and carries off the expired air, whilst the other supplies the fresh air to be breathed. ”

“ It is clear, in fact, that the air introduced by force cannot escape when the piston-rod is raised, since the valve, pressed by the internal air, remains closed. If then, replacing the tube, ΡΣ, in a vertical position, we set up a communication again between the corresponding apertures, the liquid will be driven to the exterior through the compressed air, and the latter will assume its normal volume again, and press in the liquid beneath it. If the quantity of compressed air is considerable, there will occur an expulsion, not only of the entire liquid, but also of the excess of air. ”

“ To bring away the heat produced by the subject, it is highly desirable that a constant flow of water of even temperature be secured. Direct connection with the city supply is not practicable, owing to the variations in pressure, and hence in constructing the laboratory building provision was made to install a large tank on the top floor, fed with a supply controlled by a ball-and-cock valve. ”

“ Then the whole velocity at any point will be inversely proportional to the radius of the point, and the fluid will describe stream lines having a constant inclination to the radius drawn to the axis of the current. That is, the stream lines will be logarithmic spirals. When water is delivered from the circumference of a centrifugal pump or turbine into a chamber, it forms a free vortex of this kind. The water flows spirally outwards, its velocity diminishing and its pressure increasing according to the law stated above, and the head along each spiral stream line is constant. ”

“ It consists of a reservoir made of sheet iron, into which the air is forced, and, by an ingeniously contrived pump, is secured like a knapsack to a man’s back, and the air is conveyed by means of a tube to the mouth of a nose, and thus into the lungs at the ordinary pressure, while a small external valve allows of the escape of the air after it has been respired. ”

“ In the gravity system the water stands in the return pipes and risers at practically the same level as that in the boiler, though in the remote parts of the system it rises above the boiler level by a height equivalent to the pressure required to effect the circulation through the system. For this reason gravity systems should be designed for free circulation, with pipes of ample size, the difference of pressure required between the steam mains and the most extreme point of the returns never exceeding a pound or two per square inch. ”

“ The water then drops into the end of the tilt which happens to be uppermost, and when quite full it falls over, throwing the water into the globe, S, from which it flows away by the waste pipe. In this way an imperfect vacuum is produced in the globe, quite sufficient to produce a draught in the small tube of the syphon, or the long leg; and the whole contents of the reservoir, G, immediately run off, and the spiral springs, b b, elevate the reservoir to its original position. To produce this action, a quarter of an inch of rain must have fallen. The registration is easily understood. ”

“ Then, by filling the reservoirs through the long tube by hydrostatic pressure, the air is excluded, while the gas is not allowed to escape. When sold on draught, it is necessary simply to connect the long tube with the draught tube, and the short tube with an air pump, when the water can be forced out by the pressure of the air, and will flow forth sparkling and delicious as at the spring, without being re-charged with gas. ”

“ If the air pipe is too small the air will bubble slowly through the water, while if it is too large it will blow out with great force, spraying and losing the water: the ratio between the cross-sectional area of the air and water pipes is about 11⁄2 to 4. ”

“ The water pressure should be produced by a head of about fifteen feet. The water must be quite free from dust and from air-bubbles. This may be effected by making it pass through a piece of tube stuffed full of flannel, or cotton-wool, or something of the kind to act as a filter. There should be a yard or so of good black india-rubber tube, about one-eighth of an inch in diameter inside, between the filter and the nozzle. It is best not to take the water direct from the water-main, but from a cistern about fifteen feet above the nozzle. ”

“ It will be assumed, of course, that there has been no loss by condensation, and that the cubic inch of water has been expanded 1700 times by its conversion into steam.
In a short time the steam will condense into water, and we now have, again, a partial vacuum in the receiver, due, of course, to the change in bulk from steam to water. Each time the liquid is heated it produces a pressure, and the pressure indicates the presence of heat; and whenever it cools a loss of pressure is indicated, and that represents cold, or the opposite of heat. ”

“ Water may be considered as 2,400 times as efficient as air, volume for volume, in condensing steam. When a condenser is made for the purpose of using water as a cooling agent, a large number of small tubes may be grouped together in a box, and the water may be pumped in at one end of the box and discharged at the other end through relatively small openings; but when air is employed, the tubes or condensing surface must be widely distributed, so that a very large amount of air is encountered, and the air which has struck one tube and become heated must never strike a second tube. ”

“ Besides merely forcing the steam and water through the radiators and piping, it is necessary to force out the air which accumulates, and to do this the system must carry a pressure somewhat above that of the atmosphere, unless a vacuum system, which will be described later, be used. ”

“ The water being previously heated to the boiling point, no condensation ensues, but the whole weight of water, which was previously balanced in two columns of equal height, is driven, by the pressure of the steam, to the side opposite to that at which the elastic vapour entered, and that side of the wheel will necessarily preponderate. ”

“ When steam is turned on it compresses the air to the pressure of the steam, and immediately fills a portion of the bottom and the nearest loops to the inlet. Each loop then acts independently and the air syphons out of each, one after another, until all are full of steam. In the hot-water type, as shown, the steam has a free circulation around the radiator as a whole, which interferes with the air circulation in each loop, so that these radiators will often remain air bound in the center for a considerable length of time. ”

“ The portion of air in immediate contact with the wadding is condensed; and if the wadding were to remain at rest, the air throughout the tube would soon acquire a uniform density. But this would require a small interval of time; for the condensation next the wadding would travel with the velocity of sound to the other end, from whence, being reflected back, a series of waves would be generated, which, aided by the friction of the tube, would ultimately destroy the motion.
But until the first wave reaches the impediment at the muzzle, the air can exert no pressure against it. ”