Water droplet

“ The splash is insignificantly small and of very short duration. [3] If the drying and polishing be not so perfect, the configurations of Series VII. are produced; while if the sphere be roughened with sandpaper, or left wet, Series VIII. is obtained, in which it will be perceived that, as was the case with the liquid drop, the water is driven away laterally, forming the ribbed basket-shaped hollow, which, however, is now prolonged to a great depth, the drop being followed by a cone of air, while the water seems to find great difficulty in wetting the surface completely. ”

“ Very beautiful forms of the same type indeed, but different in detail, are those produced by a drop of water falling into the lighter and more mobile liquid, petroleum.
It will now be interesting to turn to the splash that is produced when a solid sphere, such as a child's marble, falls into water. ”

“ The drop it self, before it be broken, appears very transparent, and towards the middle of it, to be very full of small Bubbles, of some kind of aerial substance, which by the refraction of the outward surface appear much bigger then really they are, and this may be in good part removed, by putting the drop under the surface of clear Water, for by that means most part of the refraction of the convex Surface of the drop is destroyed, and the bubbles will appear much smaller. ”

“ As the drop descends the hollow becomes wider and deeper, and finally closes over the drop (Fig. 3) , which, however, soon again emerges as the hollow flattens out, appearing first near, but still below the surface (Fig. 4) , in a flattened, lobed form, afterwards rising as a column somewhat mixed with adherent water, in which traces of the lobes are at first very visible.
The rising column, which is nearly cylindrical, breaks up into drops before or during its subsequent descent into the liquid. ”

“ The detachment of the drop is a dynamical effect, and it is influenced by collateral circumstances. For example, the bore of the tube is no longer a matter of indifference, even though the attachment of the drop occurs entirely at the outer edge. It appears that when the external diameter exceeds a certain value, the weight of a drop of water is sensibly different in the two extreme cases of a very small and of a very large bore. ”

“ The undermost parts of a drop of water on a support are pressed against the support, and the upper parts are pressed against the lower parts because the latter cannot yield. But when a drop falls freely downward all its parts move equally fast; no part is impeded by another; no part presses against another. A freely falling drop, accordingly, is not affected by its weight; it acts as if it were weightless; it assumes a spherical form.
A moment's glance at the soap-film figures produced by our various wire models, reveals to us a great multiplicity of form. ”

“ Absorption and Filtration.—The process of under-draining is a process of absorption and filtration, as distinguished from surface-flow and evaporation. The completeness with which the latter are prevented, and the former promoted, is the measure of the completeness of the improvement. If water lie on the surface of the ground until evaporated, or if it flow off over the surface, it will do harm; if it soak away through the soil, it will do good. ”

“ It will not be possible to drain off the last drop of water; but if the gold is coherent, the crucible can be so inclined that this drop drains away from the gold, in which case the drying can be done rapidly; the boiling of the water will do no harm. ”

“ That in time of flood a large proportion, both of the suspended and dissolved filth, is conveyed down to the intakes, and in ordinary weather considerable portion of soluble organic matter makes its way to the pumping works, and is still present in the water distributed to the consumers. ”

“ And that it is also different from common elastic air, is sufficiently proved by daily experience; for lime-water, which soon attracts air, and forms a crust when exposed in open and shallow vessels, may be preserved, for any time, in bottles which are but slightly corked, or closed in such a manner as would allow free access to elastic air, were a vacuum formed in the bottle. ”

“ There is no outlet above ground, no stream flowing from it, and it is, of course, a stagnant water, with no other circulation than than which springs from the changes in temperature and from the gas and petroleum that are constantly rising through the pool. ”

“ The little spherical masses of water join together so as to form raindrops in some manner not well understood. When enough of them coalesce so that the weight of the drop is too heavy to be supported by the motions of the air it falls to the ground, or is evaporated by the warmer and drier lower air. ”

“ The flux and reflux, when seen were quite regular. Every flood began gently, its velocity increasing by degrees, until at length it rushed in with great impetuosity, till it had attained its full hight. Having remained for a little time stationary, it then retired, ebbing gently at first, but afterward sinking away with great swiftness. At every flux the whole body of water seemed to be violently thrown against the bank; but neither during the time of the flux, nor that of the reflux, did there appear even the least wrinkle of a wave on the other parts of the moat. ”

“ This movement will cause much of the sediment that has adhered to the sides of the bag to fall down. Now untie your bottle and set it aside and let the water run through the bag to clean it. If you have a filter attached to your kitchen faucet you can get a very [29] good idea of the solid contents of the water by unscrewing it, or turning it over if it is made so as to reverse, and letting the sediment that has collected on it drip into a tumbler, but the bag gives much better results, as many of the delicate forms that live in the water are crushed to death on the filter. ”

“ In case it is lost by evaporation it must condense and fall to the ground somewhere near the works in which it is used, and if it floats away in the water it must eventually find a resting place on the bottom of the stream in which it is carried away. ”

“ We have seen, that evaporation proceeds much more rapidly from a surface of water, as a pond or river, than from a land surface, unless it be fully saturated, and that evaporation from the water exceeds the whole amount of rain, about as much as evaporation from the land falls short of the amount of rain. ”

“ The drop-down curve is caused by a sudden steepening of the slope of the invert; by allowing a free discharge; or by allowing a discharge into a body of water whose surface elevation would be below the surface of the water in the sewer, at the point of discharge, under conditions of steady, uniform flow with the given rate of discharge. The last described condition is common at the outlet of many sewers, hence the common occurrence of the drop-down curve.
The hydraulic jump is a phenomenon which is seldom considered in sewer design. ”

“ Every considerable addition to its water wells up, and soaks its very surface; and that which is added after it is already brim full, must flow off over the surface, or lie in puddles upon it. Evaporation is a slow process, and it becomes more and more slow as the level of the water recedes from the surface, and is sheltered, by the overlying earth, from the action of sun and wind. ”

“ The same operation takes place in the soil. When the air is allowed to circulate among its lower and cooler, (because more shaded,) particles, they receive moisture by the same process of condensation. Therefore, when, by the aid of under-drains, the lower soil becomes sufficiently loose and open, to allow a circulation of air, the deposit of atmospheric moisture will keep it supplied with water, at a point easily accessible to the roots of plants. ”

“ But there are two kinds of water-spouts, the first of which, alluded to above, is no other than a thick compressed cloud, reduced to a small space by contrary winds, which, blowing at the same time from many corners, give it a cylindric form, and causes the water to fall by its own weight. The quantity of water is so great, and the fall so sudden and precipitate, that if unfortunately one of these spouts breaks on a vessel, it shatters it to pieces and sinks it in an instant. ”

“ The soil is rendered cold by evaporation. If water cannot pass through the land by drainage, either natural or artificial, it must escape, if at all, at the surface, by evaporation. Now, it is a fact well known, that the heat disappears, or becomes latent, by the conversion of water into vapor. Every child knows this, practically, at least, who, in Winter, has washed his hands and gone out without drying them. ”

“ 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. ”

“ From the lashed and rippling sea surface, where it upcones into the base of the spout, some water is carried aloft as spray mingling with the mist of the chilled vapor, but not necessarily in very large proportion, and never rising in solid body to the cloud, as popularly supposed. On the contrary, waterspouts, however massive and formidable looking, are very tenuous, and may occur on land or water indifferently. ”

“ For the vehemency of the heat of the drop causes such hidden motions and bubbles in the cold Water, that some parts of the Water bear more forcibly against one part then against another, and consequently do more suddenly cool those parts to which they are contiguous. ”

“ Wherefore a muddy sediment settles quietly on the bottom of vessels, and oil remains on the top of the water and is not sent further away. A drop of water remains intact on a dry surface, and is not expelled from the dry substance. ”

“ The supply of water is now far in excess of the means provided at the surface for its care, and it has been found necessary to ditch from the well to the river to carry it away. The pipes are at all times in danger of bursting—the sudden blasts of air and foreign substances rendering it more or less dangerous to go near the opening. ”

“ Puddling is merely the working of wet clay, or other soil, by beating, or treading, or stirring, until its particles are so finely divided that water has an exceedingly slow passage between them, with ordinary pressure. We see the effect of this operation on common highways, where water often stands for many days in puddles, because the surface has been ground so fine, and rendered so compact, by wheels and horses, that the water cannot find passage. ”

“ When the spout breaks, a considerable part of the water in the air drops in a torrential deluge. Popular tradition has it that sea water drawn into a spout falls as fresh water—a tradition that is contrary to the facts of the case. ”

“ Whenever a wet spot is observed, seek for the cause, and be satisfied whether it is wet because a spring bursts up from the bottom; or because the subsoil is impervious, and will not allow the surface-water to pass downward. Ascertain carefully the cause of the evil, and then skillfully doctor the disease, and not the symptoms merely. A careful attention to the theory of moisture, will go far to enable us properly to determine the requisite frequency of drains. ”

“ The effect of thus alternately forcing high-pressure steam among the sand, and of discharging high-pressure water contained in the sand into the well, is to break up any cohesion of the sand, and to allow all the finer particles in the neighbourhood of the orifice to rush out with the water through the wire gauze into the well. ”

“ To produce them, there must be a continued action of heat and evaporation. If we draw off effectually and constantly the bottom water from beneath the clay and from its substance, as far as it admits of percolation, and by some other means provide a vent for the upper water, which needs no more than this facility to run freely, there seems good reason to suppose that the object may be completely attained, and that we shall remove the moisture from both portions as effectually as its quantity and the substance will permit. ”

“ He found that deep drains began to run after wet weather, not from the water above, but from the water rising from subterranean accumulations below, and that by draining the stagnant moisture from three or four feet of earth next the surface, it was rendered more friable and porous, easier to work, and more easily penetrated by the rain. The rain carried down air which, being full of ammonia and manure, made the earth below warmer, and therefore more genial to the roots of the crops. ”

“ By heating water over a fire, bubbles rise from the bottom of the vessel, adhere awhile to the sides of it, and then ascend to the surface, and burst and go off in visible vapor, or, in other words, by evaporation. Water is evaporated by the heat of the sun merely, and even without this heat, in the open air. It is evaporated at very low temperatures, when fully exposed to the air. Even ice evaporates in the open air. We often observe in Winter, that a thin covering of ice or snow disappears from our roads, although there has been no thawing weather. ”

“ The mud drum is attached to a boiler with the expectation that it will catch and hold the larger portion of the sediment precipitated from the water. The mud drum to be effective should be protected from the heat of the fire, for so soon as it receives sufficient heat to boil the water within it can no longer serve the purpose for which it was intended as all the sediment which may have gathered would be expelled by the ebullition of the water. ”