There was evaporation of water from the leaf.
An economical method of evaporation must be found.
The annual evaporation from water surfaces is from 60 to 150 in.
The test tube is tightly corked to prevent evaporation, and allowed to stand for some hours.
Cadmium sulphate, CdSO 4, is known in several hydrated forms; being deposited, on spontaneous evaporation of a concentrated aqueous solution, in the form of large monosymmetric crystals of composition 3CdSO 4.8H 2 O, whilst a boiling saturated solution, to which concentrated sulphuric acid has been added, deposits crystals of composition CdSO 4 4H 2 0.
The sugar thus produced, by constant stirring and evaporation almost to dryness, forms a species of small-grained concrete.
The processes of evaporation and concentration are carried on as they are in a cane sugar factory, but with this advantage, that the beet solutions are freer from gum and glucose than those obtained from sugar-canes, and are therefore easier to cook.
It is only known in solution; evaporation of the solution yields the pentoxide.
In endeavouring to make a pan of less power do as much and as good work as one of greater power, they have imagined many ingenious mechanical contrivances, such as currents produced mechanically to promote evaporation and crystallization, feeding the pan from many points in order to spread the feed equally throughout the mass of sugar being cooked, and so on.
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.
Evaporation of the Juice to Syrup. - The third operation is the concentration of the approximately pure, but thin and watery, juice to syrup point, by driving off a portion of the water in vapour through some system of heating and evaporation.
In the upper part of the river the reservoirs are partially protected by curtains of verdure from the effects of the evaporation which makes itself so severely felt on the treeless seaboard.
In the best days of the so-called Jamaica Trains in Demerara, three-quarters of a ton of coal in addition to the megass was burned per ton of sugar made, and with this for many years planters were content, because they pointed to the fact that in the central factories, then working in Martinique and Guadeloupe, with charcoal filters and triple-effect evaporation, 750 kilos of coal in addition to the megass were consumed to make woo kilos of sugar.
Unfortunately no observations of evaporation from the surface of the open sea have been made and very few comparisons of the evaporation of salt and fresh water are on record.
Others are deprived of a part of their more volatile constituents by spontaneous evaporation, or by distillation, in vacuo or otherwise, at the lowest possible temperature.
We can calculate the heat of formation from its ions for any substance dissolved in a given liquid, from a knowledge of the temperature coefficient of ionization, by means of an application of the well-known thermodynamical process, which also gives the latent heat of evaporation of a liquid when the temperature coefficient of its vapour pressure is known.
That evaporation in vacuo, in a multiple-effect evaporator, is advantageous by reason of the increased amount of sugar obtained from a given quantity of juice, and by reason of economy of fuel, there is no doubt, but whether such an apparatus should be of double, triple, quadruple or quintuple effect will depend very much on the amount of juice to be treated per day, and the cost of fuel.
Some crystallizers are made entirely cylindrical, and are connected to the condenser of the vacuum pan; in order to maintain a partial vacuum in them, some are fitted with cold-water pipes to cool them and with steam pipes to heat them, and some are left open to the atmosphere at the top. But the efficiency of all depends on the process of almost imperceptible yet continuous evaporation and the methodical addition of syrup, and not on the idiosyncrasies of the experts who manage them; and there is no doubt that in large commercial processes of manufacture the simpler the apparatus used for obtaining a desired result, and the more easily it is understood, the better it will be for the manufacturer.
The first volume, Vegetable Staticks (1727), contains an account of numerous experiments in plant-physiology - the loss of water in plants by evaporation, the rate of growth of shoots and leaves, variations in root-force at different times of the day, &c. Considering it very probable that plants draw "through their leaves some part of their nourishment from the air," he undertook experiments to show in "how great a proportion air is wrought into the composition of animal, vegetable and mineral substances"; though this "analysis of the air" did not lead him to any very clear ideas about the composition of the atmosphere, in the course of his inquiries he collected gases over water in vessels separate from those in which they were generated, and thus used what was to all intents and purposes a "pneumatic trough."
In a general way this greater complexity may be said to consist (I) in the restriction of regular absorption of water to those parts of the plant-body embedded in the soil, (2) in the evaporation of water from the parts exposed to the air (transpiration).
The latter function has been found to be of extreme importance in the case of plants exposed to the direct access of the suns rays, the heat of which would rapidly cause the death of the protoplasts were it not employed in the evaporation of the water.
The evaporation which is associated with transpiration is no doubt another, but by themselves they are insufficient to explain the process of lifting water to the tops of tall trees.
In the summer a great accumulation of solar heat takes place on the dry surface soil, from which it cannot be released upwards by evaporation, as might be the case were the soil moist or covered with vegetation, nor can it be readily conveyed away downwards as happens on the ocean.
Evaporation and subsequent distillation under a high vacuum gives crude glycerin.
The impure glycerin obtained as above is purified by redistillation in steam and evaporation in vacuum pans.
In 1899, at Maidstone, special prizes were offered for machines for washing hops with liquid insecticides, cream separators (power and hand), machines for the evaporation of fruit and vegetables, and packages for the carriage of (a) soft fruit, (b) hard fruit.
The evaporation from this large basin exercises a certain influence on the climate of the surrounding country, while the absorption of heat for the thawing of the ice has a notable cooling effect in early summer.
The excess of heat received in equatorial regions expands the water, but at the same time excess of evaporation concentrates it, so that the density increases.
Evaporation of the water and anything that lowers the hydrogen-ion concentration have the same effect.
In one process the purified ore is disintegrated with hot nitric acid to produce nitrates, which are then converted into sulphates by evaporation with sulphuric acid.
If it be rubbed in or evaporation be prevented, it acts, like alcohol and chloroform, as an irritant.
The solution on evaporation deposits a hydrated form, H 2 SiF 6.2H 2 O, which decomposes when heated.
The evaporation of the juice to syrup point.
The growing demand for this system of evaporation for application in many other industries, besides that of sugar has brought to the front a large number of inventors.
The defecated cane juice, having lost about 70% of its bulk by evaporation in the multipleeffect evaporator, is now syrup, and ready to enter the vacuum pan for further concentration and crystallizaHoward's tion.
The use of multiple-effect evaporation made it possible to raise the steam for all the work required to be done in a well-equipped factory, making crystals, under skilful management, by means of the bagasse alone proceeding from the.
If, on the other hand, the alcohol be rubbed into the skin, or if its evaporation be prevented - as by a watch-glass - it absorbs water from the tissues and thus hardens them.
The process of natural evaporation in the salines or salt gardens of the margin of warm seas made the composition of sea-salt familiar at a very early time, and.
Annually, but the drainage from the eastern slopes of the Andes is large enough to meet the loss from evaporation and keep these inland lakes from drying up. At an early period this depressed area drained southward to the Colorado, and the bed of the old outlet can still be traced.
During the three years he held this position he carried out researches on the contact of elastic solids, hardness, evaporation and the electric discharge in gases, the last earning him the special commendation of Helmholtz.
What is not used in the constructive processes is employed in the evaporation of the water, the leaf being thus kept cool.
In the case of a large hollow in a very dry climate the rate of g evaporation may be sufficient to prevent the water from ever rising to the lip, so that there is no outflow to the sea, and a basin of internal drainage is the result.
During the formation of the Schlier the plain was covered by an inland sea or series of salt lakes, in which evaporation led to the concentration and finally to the deposition of the salts contained in the water.
It is found that in reducing the juice of these two qualities to syrup, fit to pass to the vacuum pans for cooking to crystals, the total amount of evaporation from the degraded j uice is about half that required from the normal juice produced by double crushing.
The proportions of the salts of river and sea-water are quite different, as Julius Roth shows thus: - The salts of salt lakes which have been formed in the areas of internal drainage in the hearts of the continents by the evaporation of river water are entirely different in composition from those of the sea, as the existence of the numerous natron and bitter lakes shows.
It was this remarkable fact which first led to the idea that, as the rainfall could not be accounted for either by evaporation or by the river discharge, much of the 90% unaccounted for must sink into the ground, and in part be absorbed by some underlying bed-rock.
Of the water received by Albert Nyanza annually (omitting the Victoria Nile from the calculation) between 50 and 60% is lost by evaporation, whilst 24,265,000,000 cubic metres are annually withdrawn by the Bahr-el-Jebel.
In length; with such coils, and a sufficient annular space in the pan free from obstruction, in order to allow a natural down-current of the cooking mass, while an up-current all round is also naturally produced by the action of the heated worms or coils, rapid evaporation and crystallization can be obtained, without any mechanical adjuncts to require attention or afford excuse for negligence.
In beetroot sugar manufacture the operations are washing, slicing, diffusing, saturating, sulphuring, evaporation, concentration and curing.
The free acid has not been isolated, since on evaporation the solution gradually loses sulphur dioxide.
The impurities occasionally present in commercial citric acid are salts of potassium and sodium, traces of iron, lead and copper derived from the vessels used for its evaporation and crystallization, and free sulphuric, tartaric and even oxalic acid.
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.