Cooley's Cyclopaedia of Practical Receipts Volume Ii Part 293

NASAL DOUCHE OF SULPHO-CARBOLATE OF ZINC. _Syn._ COLLUNARIUM ZINCI SULPHO-CARBOLATIS. _Prep._ Sulpho-carbolate of zinc, 2 grams; water, 1 oz.; dissolve.--_Use._ Antiseptic.

=Washes, Tooth.= See _above_.

=WASHING (as applied in Chemistry).= In the chemical laboratory the washing of precipitates is an operation of constant occurrence, and as the accurate result of the quant.i.tative a.n.a.lysis in which the process of precipitation is had recourse to, essentially depends upon the manner in which the washing has been carried out, we have thought it desirable in the interest of the worker commencing practical chemistry to amplify under the present section the remarks which occur under the article 'Precipitation.' In washing a precipitate the object is, of course, to entirely free it from all extraneous matter, so as to ensure, after proper drifting, its being weighed in an absolutely pure and uncontaminated state. To arrive at a correct knowledge as to when a precipitate has been properly washed, the operator must never trust to guesswork, but to _ocular demonstration_, by testing a minute portion, such as a drop or so of the washings, from time to time.

This may be done, either by adding--1. A very minute quant.i.ty of the proper precipitant[259] to the washings; or--2. By evaporating a drop of the latter on a platinum knife, or a piece of platinum foil; when, if in the former case no turbidity is caused and in the latter no fixed residue remain, the precipitate may be p.r.o.nounced perfectly washed. The operator, however, instead of not sufficiently washing his precipitate, is frequently liable to fall into another dilemma, which consists not so much in overwashing it as in washing it with an unsuitable liquid, or one in which the precipitate is, to a greater or lesser extent, soluble.

[Footnote 259: See PRECIPITATE]

It may not unfrequently happen that the best available precipitant may be one in which the precipitate is soluble to some small extent. Under these circ.u.mstances, before throwing down the precipitate, the liquid should, as far as practicable, be removed by evaporation.

Many precipitates which are not altogether insoluble in water may, by the addition of some other liquid to the water, be rendered much less so.

Thus, the double chloride of platinum and ammonium which is incompletely thrown down in water is perfectly precipitated if alcohol be added to the water, as are also chloride of lead and sulphate of lime, whilst the basic phosphate of magnesium and ammonium may be rendered insoluble in water by the addition of ammonia to the water. The precipitate having subsided to the bottom of the fluid in which it was suspended, the supernatant liquid may be removed from it either by filtration or decantation. In some cases both processes are had recourse to. To wash a precipitate which has been separated by filtration, and which in a moist condition more or less fills the paper-filter inserted in a proper funnel, the wash-bottle described below is employed. In using this apparatus the jet of water that is made to issue from the bottle should be denoted upon the sides of the filter, and never in the centre, since this would cause a splashing and a consequent loss of the precipitate. The same contingency would be liable to follow it the waters were propelled too violently from the bottle. On no account must the wash-water be allowed to reach to the top of the filter. Another precaution to be guarded against is the formation in the precipitate of fissures or channels; if these are not prevented, the water will not permeate all the parts of the precipitate, and it will be only very insufficiently washed. When such channels form, it will be best to stir up the precipitates with a gla.s.s rod or a platinum spatula, taking care, however, to avoid tearing or making a hole in the filter.

Precipitates that are washed by decantation ought to consist of such substances as readily subside from the liquid in which they are suspended and are practically insoluble in water, since a very much larger quant.i.ty of this menstruum has to be employed than when filtration is had recourse to. The process is generally carried out in deep vessels. The supernatant liquid being removed, the vessel is filled up with water, and the precipitate well stirred up with a gla.s.s rod; after it has again fallen down fresh water is added, and the process is continued until the washings cease to show the presence of any soluble matter. The several washings being collected, are let stand some 12 or 24 hours; after which time, should no precipitate show itself, they are thrown away. Should any deposits form in the washing, it is carefully removed either by filtration or decantation, and its amount being determined, the result is added to that obtained from the bulk of the precipitate. Where the nature of the precipitate is in no way influenced by hot water, this latter should always be used in washing precipitates, as it greatly facilitates and expedites the operation. Many precipitates require to stand a long time before they entirely subside from the fluid in which they are suspended.

Most gelatinous, pulverulent, and crystalline precipitates are of this nature. The separation of the precipitate should not be attempted until after the liquid containing the precipitate has stood several hours.

=WASHING FLU'IDS.= Solutions of carbonate of soda, rendered caustic with quicklime.

=WASHING POW'DERS.= See POWDERS.

=WATCH'FULNESS.= _Syn._ SLEEPLESSNESS. AGRYPNIA, L. The common causes of watchfulness are thoughtfulness or grief, disordered stomach or bowels, heavy and late suppers, and a deficiency of outdoor exercise. The best treatment, in ordinary cases, simply consists in an attention to these points. The method of producing sleep recommended by a late celebrated hypnotist consists in merely adopting an easy rec.u.mbent position, inclining the head toward the chest, shutting the eyes, and taking several deep inspirations with the mouth closed. Another method, recommended by an eminent surgeon, and which appears infallible if persevered in with proper confidence, and which is suitable either to the sitting or rec.u.mbent posture, consists in tying a decanter cork with a bright metallic top, a pencil-case, or any other bright object on the forehead, in such a position that the eyes must be distorted or strained to be capable of seeing it. By resolutely gazing in this way for a short time, without winking, with the mind fully absorbed in the effort, the muscles of the eyes gradually relax, and the experimenter falls asleep. Gazing in a similar manner on any imaginary bright spot in the dark, as at night, exerts a like effect. A tumblerful of cold spring water, either with or without a few grains of bicarbonate of potash in it, taken just before lying down, will frequently succeed with the dyspeptic and nervous, when all other means fail.

The following valuable advice to those who suffer from unnatural wakefulness is abridged from the late Dr Tanner's valuable work on the 'Practice of Medicine.'[260]

[Footnote 260: 'The Practice of Medicine,' by Thos. Hawkes Tanner, M.D., Renshaw, London.]

As his starting point Dr Tanner enjoins the practice of taking a proper amount of exercise daily. A digestible diet, such as is not liable to cause acidity or flatulence, must also be adopted, and tea and coffee must be abstained from in the after part of the day. Early dinners and light suppers are also recommended. The reading of any thrilling work of fiction previous to retiring to rest is also prohibited. The patient is advised to seek his bed at an early and regular hour, and it is desirable to have his sleeping chamber well ventilated, and if the weather be chilly the bedroom fire should be lighted. Feather beds should be abandoned for mattresses; there should not be too many blankets on the bed, the pillows should be firm and high, and no curtains or hangings should be allowed. Should the above means fail to produce the required sleep, before going to bed the patient is advised to try a tumbler of port-wine negus, or of mulled claret, or of white-wine whey, the last thing. The aged are recommended (should the above methods be unsuccessful) to imbibe a gla.s.s of spirit and water, which is said to be all the more effective if drunk when in bed. In some cases, attended by a hot or dry skin, a gla.s.s of cold water has been found useful. Another remedy is the use of a bath, for about three or five minutes, just before getting into bed, at a temperature varying from 90 to 96 F.

Rapid sponging of the body with tepid water is also recommended, as also the use of a warm foot bath, at a temperature of 100 F., or of a hot-water bottle in the bed, or putting the feet in cold water for a minute, and then vigorously rubbing them.

For those whose sleeplessness is caused by their prosecuting literary work till a late hour a short brisk walk, just before retiring to bed, is recommended.

If the wakefulness can be traced to any bodily ailment, this, of course, must be removed by the proper means. Constipation, which is not at all an unfrequent cause of insomnia, must be combated by the methods described under that article. If there be headache it will be best removed by applying a rag dipped in cold water to the scalp, or a bladder containing ice.

Should the adoption of any of the above suggestions fail all kinds of mental labour and excitement during the day must be greatly diminished, and physical exercise must replace them. Sedatives should be had recourse to with great caution, and under medical supervision only. Because of the hazard attending their use, and of the ready tendency their adoption has to degenerate into a pernicious ineradicable habit, we have forebore to specify the medicinal agents Dr Tanner prescribes for sleeplessness, strongly recommending the patient, before he has recourse to them, to exhaust the category of suggestions given by Dr Tanner, and, should these unhappily be found to fail, and he is drawn to soporifics, we again reiterate, let him take them only under medical supervision.

Another method, adopted by professional hypnotists, consists in gently moving, in opposite directions, a finger of each hand over the forehead, just above the eyebrows. A soothing and drowsy effect is said to be thereby produced, which ends in tranquil slumber.

Dr Ainslie Hollis contributes some excellent hints on the treatment of wakefulness to the pract.i.tioner. He cla.s.sifies the treatment under two heads--first, the induction of natural sleep, and, secondly, the production of narcosis or artificial rest. The application of mustard plasters to the abdomen generally brings about the first result, producing, according to Schuler, first dilatation, and subsequently contraction of the vessels of the pia mater. Dr Pleyer, of Jena, on the supposition that sleep may be induced by the introduction of the fatigue products of the body, advocates the administration of a solution of lactate of soda. When sleeplessness is the result of brain exhaustion Dr Hollis advocates a tumbler of hot claret negus. The alkalies and alkaline earths, says the 'Boston Journal of Chemistry,' are useful when acid dyspepsia is a.s.sociated with the insomnia. In hot weather, sprinkling the floor of the sleeping apartment with water lessens the irritant properties of the air, adding much to the comfort of the sleepers; possibly the quant.i.ty of ozone is at the same time increased. When sleep is broken by severe pain, opium or morphia is of value, bringing not only relief, but producing anaemia of the cerebral vessels; when neuralgia is the cause an injection of morphia under the skin, near the branch of the affected nerve, will have more effect than by administering it by the mouth.

Again, when wakefulness is due to defective cardiac power, digitalis may be useful. Chloral hydrate is supposed to owe its hypnotic effect to its power of diminishing the amount of blood in the brain, and therefore it may be used when sleeplessness arises from the pains of muscular spasm.

The bromides, although undoubtedly sedatives, possess very doubtful hypnotic properties. See SUPPER, &c.

=WA'TER.= H_{2}O. _Syn._ OXIDE OF HYDROGEN, PROTOXIDE OF H.; AQUA, L.; EAU, Fr.; Wa.s.sER, Ger.; ?d??, Gr. The ancients regarded water as a simple substance, and as convertible into various mineral and organic products.

Earth, air, fire, and water were at one time conceived to be the elementary principles or essences of matter from which all form and substance derived their existence. The true const.i.tution of water was not discovered until about the year 1781, when Cavendish and James Watt, independently and nearly simultaneously, showed it to be a compound of hydrogen and oxygen. Five years, however, before this time (1776), the celebrated Macquer, a.s.sisted by Sigaud de la Fond, obtained pure water by the combustion of hydrogen in the air. It has since been satisfactorily demonstrated that hydrogen and oxygen exist in water in the proportion of 1 to 8 by weight, or 2 to 1 by volume; the sp. gr. of hydrogen being to that of oxygen as 1 to 16. One cubic inch of perfectly pure water at 62 Fahr., and 30 inches of the barometer, weighs 252458 gr.; by which it will be seen that it is 770 times heavier than atmospheric air. Its sp.

gr. is 10, it being made the standard by which the densities of all solid and liquid bodies are estimated. The sp. gr. of frozen water (ice) is 9175, water being 10 (Dufour); that of aqueous vapour (steam), 6252, air being 10. Water changes its volume with the temperature; its greatest density is about 39-1/2 Fahr., and its sp. gr. decreases from that point, either way. Water is nearly incompressible. By subjecting water to a pressure of 705 atmospheres, Cailletet found the compressibility to be at the rate of 0004451 for each atmosphere. Water evaporates at all temperatures; but at 212 under ordinary circ.u.mstances, this takes place so rapidly that it boils, and is converted into vapour (steam), whose bulk is nearly 1700 times greater than that of water.

_Var._ Of these the following are the princ.i.p.al:

DISTILLED WATER; AQUA DESTILLATA (B. P., Ph. L., E., & D.), L. Obtained by the distillation of common water through a block-tin worm, rejecting the first and last portions that come over. The still employed for this operation should be used for no other purpose; and when great nicety is required, the distillation should be performed in gla.s.s or earthenware. It remains limpid on the addition of lime water, chloride of barium, nitrate of silver, oxalate of ammonium, or hydrosulphuric acid. It is the only kind of water that should be employed in chemical and pharmaceutical operations. When distilled water is not at hand, clean filtered or clarified rain water is the only kind that can be successfully subst.i.tuted.

NATURAL WATERS. In respect of wholesomeness, palatability, and general fitness for drinking and cooking, natural waters may be cla.s.sified in orders of excellence as follows ('Rivers Pollution Commissioners' Sixth Report'):--

{1. Spring water } Very palatable.

_Wholesome_ {2. Deep-well water } {3. Upland surface water } Moderately palatable.

{4. Stored rain water } _Suspicious_ {5. Surface water from cultivated lands } {6. River water to which sewage gains } Palatable.

_Dangerous_ { access } {7. Shallow well water }

The average composition of the four cla.s.ses of unpolluted waters is given by the same authorities as follows. Their estimations are in parts per 100,000, but may be converted in grains per gallon by multiplying by 7 and dividing by 10:

--------------+------+-------+--------+-----+--------+-------- Nitrogen Total Total Organic Organic Ammo- as combined solid Carbon Nitrogen nia nitrates nitrogen im- and purity nitrites --------------+------+-------+--------+-----+--------+-------- Rain water 295 070 015 029 003 042 Upland surface water 967 322 032 002 009 042 Deep-well water 4378 061 018 012 495 522 Spring water 2820 056 013 001 383 396 --------------+------+-------+--------+-----+--------+--------

--------------+---------+--------+----------------- Previous Hardness sewage +-----+-----+----- or animal Chlorine Temp- Perm- Total contamin- orary anent ation --------------+---------+--------+-----+-----+----- Rain water 42 22 4 5 3 Upland surface water 10 113 15 43 54 Deep-well water 474 511 158 92 25 Spring water 3559 249 110 75 185 --------------+---------+--------+-----+-----+-----

RAIN WATER contains, among natural waters, the smallest amount of solid matter in solution. From the columns headed "Organic Carbon" and "Organic Nitrogen" it will be seen that even rain collected with special precautions, away from any large town, is by no means free from organic matter. Rain water collected from roofs and stored in underground tanks is often very impure.

SURFACE WATERS form the main supply of rivers. If collected from high uncultivated districts they are usually unpolluted with animal matter. The organic matter is usually peaty, is sometimes very small, but is liable to considerable variations with the season, and is occasionally present in excessive quant.i.ties, discolouring the water and rendering it unpalatable.

From their softness these waters are admirably adapted for manufacturing purposes. The amount of solid matter in solution ranges from 2 to 7 grains per gallon.

SURFACE WATER from _cultivated land_, contains on an average less organic matter than upland surface water, but the pollution, being derived from manure and other objectionable matter, is more harmful.

RIVER WATER consists of the above, aided by springs, and most frequently the drainage of towns on its banks. The amount of solid matter varies from 10 to 30 grains per gallon. In Thames water there are on the average about 20 grains.

WELLS, if _shallow_, are usually a most undesirable supply. Unless far from any house they are contaminated by drainage, and sometimes, from proximity to cesspools, contain more animal matter than ordinary town sewage. They are, as a cla.s.s, hard waters, the polluted ones excessively so.

Wells of 100 feet deep and upwards are, as a cla.s.s, very superior waters, the filtration and oxidation of so great a depth of soil having removed the greater part of the organic matter. The hardness varies with the strata, but, as a cla.s.s, the deep wells are softer than the shallow.

SPRING WATER greatly resembles deep well water, possessing all its good qualities in a higher degree. Spring and deep well water are very uniform in quality, and little affected by climatic changes.

SEA WATER. The characteristic of this variety is its saltness. Its density is about 10274, and the average quant.i.ty of saline matter which it contains is about 3-1/2 per cent., of which about 27/35 are chloride of sodium, and the remainder chiefly chloride of magnesium and sulphate of magnesium.

The average proportion of organic carbon and nitrogen in 23 samples of sea water was 278 carbon, 165 nitrogen, as compared with Thames water averages of 203 parts carbon, 033 nitrogen, in 100,000 parts of water.

_a.n.a.lysis of sea water_ (British Channel), by Dr Schweitzer, of Brighton:--

1000 gr. contained-- Grains Water 963745 Chloride of sodium 28059 Chloride of pota.s.sium 0766 Chloride of magnesium 3666 Bromide of magnesium 0029 Sulphate of magnesium 2296 Sulphate of calcium 1406 Carbonate of calcium 0033 -------- 1000

_Pur._ Pure water is perfectly transparent, odourless, and colourless, and evaporates without residue, or even leaving a stain behind. The purest natural water is that obtained by melting snow or frozen rain, that has fallen at some distance from any town. Absolutely pure water can only be obtained by the union of its gaseous const.i.tuents; but water sufficiently pure for all purposes may be procured by the careful distillation of common water.

Among the methods adopted for improving the quality of water are:

(_a_) _For reducing the amount of organic and suspended matter._--1.

Filtration through or agitation with coa.r.s.ely powdered, freshly burnt charcoal, either animal or vegetable, but preferably the former. When in good condition a filter of animal charcoal will not only remove suspended matter in water, but will considerably reduce the amount of organic matter, and also the calcareous and gaseous impurities held in solution; but it, however, loses its power of removing lime in a week or two, and of abstracting the organic matter in about three to four months, and then becomes foul, and requires to be recharged. Spongy metallic iron is more energetic in its action than charcoal, and remains serviceable for a twelvemonth. 2. Free exposure to the action of the air, by which the organic matters become oxidised and insoluble, and speedily subside. This may be easily effected by agitating the water in contact with fresh air, or by forcing air through it by means of bellows. 3. The addition of a little sulphuric acid has a like effect; 15 or 20 drops are usually sufficient for a gallon. This addition may be advantageously made to water intended for filtration through charcoal, by which plan at least 2/3 of the latter may be saved. (Lowitz.) 4. An ounce of powdered alum (dissolved), well agitated with a hogshead or more of foul water, will purify it in the course of a few hours, when the clear portion may be decanted. When the water is very putrid about 1/2 dr. (or even 1 dr. per gall.) may be employed; any alum that may be left in solution may be precipitated by the cautious addition of an equivalent proportion of carbonate of sodium. 5. A solution of ferric sulphate acts in the same way as alum; a few drops are sufficient for a gallon. 6. Agitation with about 1/2 to 1 per cent. of finely powdered black oxide of manganese has similar effect to the last. 7. The addition of a little aqueous chlorine, or chlorine gas, to foul water, cleanses it immediately. This method has the advantage of the water being perfectly freed from any excess of the precipitant by heat.

(_b_) _For reducing amount of inorganic matter._--1. Distillation separates all non-volatile matter, including organised bodies. It is used to obtain a potable water from sea water. The waste heat of the cook's galley is amply sufficient for this purpose. There are several patent contrivances for the distillation of water on ship board. 2. Hard water may be softened by adding carbonate of soda to the water so long as it turns milky. The precipitation of the hardening ingredients, lime and magnesia, is most rapid when the water is heated. The water cannot be used for drinking purposes, from the unpleasant flavour of the carbonate of soda. When used on a hard water intended for washing, it effects a saving of soap equal to about fifteen times its own cost. Sea water can be made fit for washing by this means. It removes both the "temporary" hardness, due to carbonates of calcium and magnesium, and the "permanent," due to the sulphates, chlorides, and nitrates of these metals. 3. Hard water may be both aerated and softened by the addition of a few grains of bicarbonate of pota.s.sium per gallon, followed by half as much lime juice or tartaric acid as is sufficient to saturate the alkali in the carbonate thus added. 4. The "temporary" hardness may be nearly removed by ebullition, or, as recommended by Professor Clarke, by mixing the hard water with lime water, when the calcium combines with the excess of carbonic acid, which previously rendered the carbonate of calcium soluble, and is precipitated as carbonate (chalk), together with the carbonate originally present. This method removes, at the same time, much of the organic matter, and carries down suspended matter. The water is often made more palatable than before. The directions are:--For every degree of hardness on Clarke's scale each 1000 gallons of water to be softened requires one ounce of quicklime. Slake the lime and work up to a thin cream with water and pour into the cistern, which already contains at least 50 gallons of water to be softened. Then add the remainder of the 1000 gallons in such a way as to stir up and mix uniformly with the contents of the cistern. In about three hours the milky water is clear enough for washing. After twelve hours' rest the water is fit to drink. If the exact hardness of the water is not known, water may be added to the milk of lime till, on adding a drop of nitrate of silver to a cupful of the cistern water, the brown tint indicative of an excess of lime is replaced by a very faint yellow. 5. To save boilers from scaling, water intended for steam purposes is sometimes treated with lime to remove carbonates, and then the sulphate of calcium (which forms a very tenacious scale) is decomposed with baric chloride (Haen's process). The precipitated mineral matter may also be prevented from forming a scale or fur by adding organic substances, such as potatoes, sound or otherwise, swedes, mangolds, or other vegetable. Oak bark, spent tan, sawdust; and their decoctions are efficacious on account of the tannic acid they contain, but they attack the boiler plates at the same time. Zinc suspended in the water is said to answer well. It has been recommended to polish the inside of the boiler plates with black lead or coat it with linseed oil and dissolved india rubber. Numerous chemical preparations, most of which do more harm than good, are also sold.

_Tests (Physical)._--1. To observe colour, stand in tall colourless gla.s.s cylinder on white ground. If very turbid allow to settle, and examine sediment by microscope for evidence of sewage contamination (linen fibres, hairs, epithelium) and for moving organisms. Slight turbidity is best noted by filling a clean quart flask and holding it towards the light with some dark object as a window pane between. Taste and odour most marked when the water is made lukewarm. 2. For poisonous metals add one drop of strong colourless ammonium sulphide to about 1000 grains of water in gla.s.s cylinder, and observe if liquid darkens. If the coloration or precipitate disappears on adding acid, it is iron; if it remains, lead or copper is present, either of which condemns the water. 3. For chlorine add couple of drops of nitric acid to a little of the water and a crystal or drop of solution of nitrate of silver. If the water turns very milky it is a bad sign; make, if possible, a comparative experiment with water of known composition. 4. The residuum, if any, of evaporation is impurity; if it be organic matter, smoke and a peculiar odour will be evolved, as the residue becomes dry and charred. 5. Neither litmus, syrup of violets, nor turmeric are discoloured or affected when moistened with pure water; if the first two are reddened it indicates an acid; if the litmus is turned blue or the turmeric is turned brown, an alkali is present. 6. If a precipitate is formed or a fur or crust deposited on the vessel during ebullition it indicates the presence of carbonates of calcium, magnesium, or iron. 7.

Calcium salts produce a white precipitate with oxalate of ammonium. 8. The liquid filtered off from 7, on standing with phosphate of sodium and ammonium (microcosmic salt), gives a white precipitate if magnesium be present. 10. Tincture or infusion of galls turns water containing iron black. When this takes place both before and after the water has been boiled, the metal is present under the form of sulphate; but if it only occurs before boiling, then ferrous carbonate may be suspected, and it will be precipitated as a reddish powder by exposure to air and heat. 11.