Chapter VII (8)

When glass vessels are exposed to damp, the best mode of writing on them is to prepare an ink for the purpose, by mixing the common cheap varnish, called Brunswick black, with half its weight of oil of turpentine, or what is the same thing, in a purer state, camphine; this should be kept in a closely corked bottle, and used with a broad nibbed quill pen; it soon dries, and though pale, is very distinct, and almost imperishable. If it is required much darker, about a quarter of an hour after it has been done, a little lamp-black should be rubbed over it, with cotton or wadding, when it immediately becomes as black as common ink, and resists damp, and rubbing or wiping with either wet or dry cloths for a very long time; the same ink is equally advantageous for use with white earthenware; and although we have never had occasion to use such a mixture, there is no doubt that a little whiting mixed thin, with any common varnish, would furnish an equally useful ink for writing on black bottles.

III.

DECANTING, STRAINING, AND FILTERING OF LIQUIDS.

The decanting of liquids is, under ordinary circumstances, an operation sufficiently simple to require no explanation; but the ease and certainty with which it can be performed, depend entirely upon the form of the vessel from which the liquid is poured; the adhesion existing between liquids and solids giving rise to the tendency in the former to run down the outside of the vessel; and, if the latter is nearly full, or very large in circumference, or the sides approach the perpendicular direction, this accident almost always occurs. The difficulty of returning a glass of wine to the decanter, or of pouring from one full tumbler into another, are well-known examples of this inconvenience.

Advantage may, however, be taken of the adhesion of liquids to solids, and by it the former may be led into the required direction. This cannot be better illustrated than by a description of the means by which a glass of wine may be returned, without spilling, to the decanter. If a tea-spoon is dipped into the wine, so as to become wetted with it, and held perpendicularly with the bowl downwards, and the point over, but not touching the entrance into the decanter, and the edge of the glass be made to touch the back of the spoon, it will be found, on inclining the former, that the wine, having a perpendicular solid body to adhere to and run down, will do so in preference to trickling along the oblique outer surface of the wine-glass; and in this mode a liquid may be poured steadily out of any similar vessel with so little disturbance as not to agitate any sediment that may exist in it. In the laboratory of the chemist, a piece of glass rod is usually employed for this purpose; but a spoon, or pencil, or any similar substance having a surface capable of being wetted by the liquid, answers equally well.

If, however, the vessel out of which it is wished to decant is large, very full, or the sides, on pouring, are nearly perpendicular, the plan is not successful; thus, it could not be employed in aiding the transfer of the liquid from one full tumbler to another. Even this may be accomplished without the aid of a funnel, or without spilling, by preventing the adhesion of the liquid to the edge or side of the vessel out of which it is poured, which may be readily done by greasing the rim, when it will be found quite practicable to pour out of a nearly full tumbler without spilling.

In many instances, the employment of a syphon in decanting will be found very advantageous, particularly when the containing vessel is large, and cannot be readily moved, or when there is any sediment which it is desirable not to disturb. The most simple form of this instrument consists of a tube, bent as in _Fig. 1_, with one leg shorter than the other; this may be made of glass, pewter, or, in fact, of any kind of stiff tubing that will retain its form—a piece of gutta-percha pipe, carefully bent by a moderate warmth, whilst a piece of stout cord is in the interior to prevent the sides closing together, answers very well. Before use, the syphon must be filled with liquor; this is best accomplished by turning it upside down, with the opening to the short leg raised on a level with that of the long one, when the liquid should be poured into the former. When both legs are filled, they should be closed with the fingers; the shorter leg introduced into the liquid it is wished to draw off; and the opening of the longer leg brought to a lower level than that of the shorter, and on removing the fingers the liquid will flow as in _Fig. 1_, until it is below the level of the short leg. If the syphon is made of small tubing, or is lessened at the openings so as not to exceed one quarter of an inch in diameter, there will be no occasion to close the end of more than one leg with the finger, as the liquid will not flow when it is brought to the proper position unless both orifices are open; and thus the necessity of plunging the finger into the liquid is obviated, and the syphon can also be used with a narrow-necked bottle, into which the hand could not be passed.

To do away with the necessity of filling the syphon before use, the instrument is usually made with a sucking tube, as in _Fig. 2_; in this case, all that is requisite is, to introduce the short leg, close the opening to the long one, and, by the action of the mouth, draw up the liquid until both legs are full, when, on removing the finger, the stream will flow. A very ingenious syphon of this kind is described by the German chemist Mohr; it is thus constructed:—Take a long Eau de Cologne bottle, and, with a file and turpentine, make a deep notch across, about an inch and a half from the bottom; then, with a charcoal point or pastile, or hot iron, produce a crack, and cut off the bottom, grinding it smoothly (all these manipulations are described in our last article, page 152); then take a tube bent at an angle of forty-five degrees, and, by means of a _good_ cork, perforated with a rat-tail rasp, fit it tightly in the bottom of the bottle, and add also another piece of tubing for a suction tube; the whole will then have the appearance represented in _Fig. 3_, and will form an exceedingly useful and very convenient syphon.

In emptying large stone bottles or carboys, the following plan may be had recourse to:—Perforate a sound cork with two openings by a rat-tail rasp, and fit, air-tight, two tubes bent as in _Fig. 4_. On blowing through the upper, the liquid will be forced to ascend and run over the bend of the other, which will then act as a syphon. This plan is exceedingly useful in emptying carboys of corrosive liquids as oil of vitriol, &c.; and if all the joints are—as they should be—air-tight, the flow may be arrested by closing the upper tube with the finger. In the figure the outer leg of the syphon is shortened to save space; in practice, it must be of sufficient length to be lower than the inner leg within the vessel.

If a syphon is required frequently for decanting the same kind of liquid, it is found troublesome to be constantly filling it before each time of using it; this trouble is obviated by the use of an instrument formed with legs of equal length, which are turned up at the ends, as in _Fig. 5_; this having been filled, may be hung up in the erect position, and the liquid will not escape, but on plunging one end into a liquid, it will be found immediately to flow from the other, provided that the latter is below the level of the surface of the liquid.

The operations of straining and filtering are frequently required in domestic manipulations, and the apparatus employed usually consists of sieves and a jelly-bag. As in many other instances, it will be found advantageous to import several contrivances from the laboratory to the kitchen; one of the most useful (because most simple) strainers consists of a square frame, formed of four pieces of wood nailed together at the corners, with a piece of calico, linen, or canvas, of suitable fineness, tacked to the four sides; this strainer is particularly useful in separating any solid substance—as the residue in making wines—or if grated potatoes are put on one made of coarse cloth, the starch can be readily washed through, leaving the useless portion on the strainer; the cloth should not be tacked very loosely, as it bags down when any substance is put on it, and the liquid runs away below from the centre. This strainer is a most useful one; it is readily made, of any degree of fineness, and of any size; and it also possesses the great advantage, that, if necessary, the tacks fastening the cloth can easily be withdrawn, when the substance remaining can be rolled up in the cloth, and tightly squeezed to express the last portions of the liquid, which are frequently the most valuable.

In cases where a finer filtration is required than can be obtained by means of a cloth, as in cleaning turbid wine or spirit, the use of filtering-paper is recommended; this paper is merely a stouter kind of blotting-paper, thick varieties of which answer very well for domestic purposes; it is most simply used by taking a square piece, folding it into half—by bringing the two opposite edges together—and then folding the oblong so obtained across its length; by this means a small square is obtained, one quarter the original size, which may be opened into a hollow cup, having three thicknesses of paper on one side, and one on the other; this is to be placed, with the point downwards, in a funnel, and the liquid poured in; and as soon as the pores of the paper are expanded by the moisture, it will be found to flow through perfectly clear; care must be taken in making the filter, not to finger it much where the two foldings cross each other, as a hole is readily made at that part, and the filter spoiled. The objection to this simple contrivance is, that from its flat sides applying themselves closely to those of the funnel, the flow of the liquid is impeded, and is, therefore, slow. This effect may be obviated by the use of the plaited filter, the construction of which we will endeavour to describe. A square piece of filtering, or stout blotting-paper, is to be doubled, and the oblong so obtained is to be again folded in half, when if the last fold is opened, it will have the appearance of _Fig. 6_. From the corners _b b_, folds are to be creased in the direction towards _a_, but not reaching it for half an inch; these are indicated by the dotted lines, which divide the double paper into four triangles, each of which is to be again folded into eighths, and care must be taken that all the folds are made the same way, that is, projecting to the same side of the paper. When complete, the double and creased paper will appear as _Fig. 7_. Now divide each eighth into half, by a fold in the _opposite_ direction to those previously made, when it will be found that the whole will fold up like a paper fan; the projecting loose ends which are formed by the corners _b_, should be cut off, and the double sides separated for the first time by blowing them apart, when the whole may be readily opened out as in _Fig. 8_. In making this filter, which takes a much less time than to follow the description, two precautions are requisite. The folds should be made at once with one firm pressure, and not with a series of rubbings; and all the creases should stop short of the middle, otherwise a hole will be made at that point, long before the filter is completed. The advantages of this filter are, that it exposes a large surface for the liquid to pass through; and from its only being in contact with the funnel where the angles project, the current flows away readily.

The best means for filtration of water, and the construction of water filters will be treated of when we speak of the “domestic manipulation” connected with that liquid.

IV.

THE MANUFACTURE AND USE OF CEMENTS.

The term cement, includes all those substances employed for the purpose of causing the adhesion of two or more bodies, whether originally separate, or divided by an accidental fracture. As the substances that are required to be connected together are exceedingly various, and differ very much in their properties as to texture, &c., &c., and as the conditions under which they are placed, with regard to heat and moisture, are also exceedingly variable, a number of cements, possessed of very different properties, are required; for a cement that answers admirably under one set of circumstances, may be perfectly useless in others. A vast number of cements are known and used in the various arts; but they may all be referred to a few classes, and our object in this paper will be to describe the manufacture and use of the best of each class, and also to state what are the general principles upon which the success or failure of cementing usually depends.

The different parts of a solid are held together by an attraction between their several particles, which is termed the attraction of cohesion, or cohesive attraction. The amount of this varies with the substance; thus, the cohesion of the particles of iron to one another is enormously great, whilst that between those of chalk is but small. This attraction acts only when the particles are in the closest possible contact; even air must not be between them. If, after breaking any substance, we could bring the particles into as close contact as before, and remove the air, they would re-unite, and be as strongly connected as ever. But, in general, this is impossible; small particles of grit and dust get between them; the film of interposed air cannot be removed; and thus, however firmly we press the edges of a broken cup together, it remains cracked china still. _Perfectly_ flat, clean surfaces, like those of freshly ground plate-glass, may sometimes be made to cohere, so that the two pieces become one, and cannot be separated without breaking. The attraction of cohesion takes place between the parts of the same substance, and must not be confounded with that of adhesion, which is the attraction of different substances to one another; for example, the particles of a piece of wood are united by cohesive attraction, whilst the union of glue and wood to each other depends on adhesive attraction. And it is important that this distinction be borne in mind, for, in almost all cases, the cohesion between the particles of the cement is very much less than the adhesion of the cement to other bodies; and if torn apart, the connected joint gives way—not by the loosening of the adhesion—but by the layer of cement splitting down the centre. Hence the important rule, that the _less_ cement in a joint, the stronger it is. Domestic manipulators usually reverse this, by letting as much cement as possible remain in the joint, which is, therefore, necessarily a weak one. A thick, nearly solid cement, which cannot be pressed out of the joint, is always inferior to a thinner one, of which merely a connecting film remains between the united surfaces.

Having thus mentioned the general principles that ought always to be borne in mind, we will now proceed to describe the manufacture of some of the more useful cements, and their mode of use.

MOUTH GLUE affords a very convenient means of uniting papers, and other small light objects; it is made by dissolving by the aid of heat, pure glue, as parchment glue, or gelatine, with about one quarter or one-third of its weight of coarse brown sugar, in as small a quantity of boiling water as possible; this, when perfectly liquid, should be cast into thin cakes on a flat surface _very_ slightly oiled, and as it cools cut up into pieces of a convenient size. When required for use one end may be moistened by the mouth, and is then ready to be rubbed on any substances it may be wished to join; a piece kept in a desk or workbox is exceedingly convenient.

PASTE is usually made by rubbing up flour with cold water and boiling; if a little alum is mixed before boiling it is much improved, being less clammy, working more freely in the brush, and thinner, a less quantity is required, and it is therefore stronger. If required in large quantity, as for papering rooms, it may be made by mixing one quartern of flour, one quarter pound of alum, and a little warm water; when mixed, the requisite quantity of boiling water should be poured on whilst the mixture is being stirred. Paste is only adapted to cementing paper; when used it should be spread on one side of the paper, which should then be folded with the pasted side inwards, and allowed to remain a few minutes before being opened and used; this swells the paper, and permits its being more smoothly and securely attached. Kept for a few days, paste becomes mouldy, and after a short time putrid; this inconvenience may be obviated by the use of—

PERMANENT PASTE, made by adding to each half-pint of flour-paste without alum, fifteen grains of corrosive sublimate, previously rubbed to powder in a mortar, the whole is to be well mixed; this, if prevented from drying, by being kept in a covered pot, remains good any length of time, and is therefore convenient; but unfortunately it is extremely poisonous, though its excessively nauseous taste would prevent its being swallowed accidentally; it possesses the great advantage of not being liable to the attacks of insects.

LIQUID GLUE.—Several preparations under this name have from time to time found their way into use. The liquid glue of the shops, however, is a totally different preparation, being inodorous, and very much cheaper. It is made by dissolving shell-lac in water, by boiling it along with borax, which possesses the peculiar property of causing the solution of the resinous lac. This preparation is convenient for its cheapness and freedom from smell, but it gives way if exposed to long-continued damp, which that made with naphtha resists.

Of the use of COMMON GLUE, very little need be said; it should always be prepared in a glue-pot or double vessel, to prevent its being burned; which injures it very materially; the objection to the use of this contrivance is, that it renders it impossible to heat the glue in the inner vessel to the boiling point; this inconvenience can be obviated by employing in the outer vessel some liquid, which boils at a higher temperature than pure water, such as saturated solution of salt (made by adding one-third as much salt as water). This boils at 224° Fahr., 12° above the heat of boiling water, and enables the glue in the inner vessel to be heated to a much higher temperature than when pure water is employed. If a saturated solution of nitre is used, the temperature rises still higher.

WATERPROOF CEMENTS are very numerous; a very good one for uniting china and glass will be found in another page. It should be stated, however, that the gum ammoniac should be also dissolved in a small quantity of spirit. Mastic, used instead of ammoniac, makes a clearer cement. This mixture, under various fanciful titles, is usually sold at a most exorbitant rate.

LIME AND EGG CEMENT is frequently made by moistening the edges to be united, with white of egg, dusting on some lime from a piece of muslin, and bringing the edges into contact. A much better mode is to slake some freshly burned lime with a small quantity of _boiling_ water; this occasions it to fall into a very fine dry powder, if excess of water has not been added. The white of egg used should be intimately and thoroughly mixed, by beating, with an equal bulk of water, and the slaked lime added to the mixture, so as to form a thin paste, which should be used speedily, as it soon sets. This is a valuable cement, possessed of great strength, and capable of withstanding boiling water. Cements made with lime and blood, scraped cheese, or curd, may be regarded as inferior varieties of it. Cracked vessels, of earthenware and glass, may often be usefully, though not ornamentally repaired by white lead spread on strips of calico, and secured with bands of twine. But in point of strength, all ordinary cements yield the palm to Jefferey’s Patented Marine Glue, a compound of India-rubber, shell-lac, and coal-tar naphtha. Small quantities can be purchased at most of the tool warehouses, at cheaper rates than it can be made. When applied to china or glass, the substance should be cautiously made hot enough to cement the glue, which should be then rubbed on the edges so as to become fluid, and the parts brought into contact immediately. When well applied, the mended stem of a common tobacco-pipe will break at any other part in preference to the junction. The colour of the glue unfortunately prevents its being used.

The RED CEMENT, which is employed by instrument makers for cementing glass to metals, and which is very cheap and exceedingly useful for a variety of purposes, is made by melting five parts of black resin, one part of yellow wax, and then stirring in, gradually, one part of red ochre or Venetian red; in fine powder, and previously _well dried_. This cement requires to be melted before use, and it adheres better if the objects to which it is applied are warmed. A soft cement, of a somewhat similar character, may be found useful for covering the corks of preserved fruit and other bottles, and it is made by melting yellow wax with an equal quantity of resin, or of common turpentine (not oil of turpentine, but the resin), using the latter for a very soft cement, and stirring in, as before, some dried Venetian red. Bearing in mind our introductory remarks, it will be seen that the uniting broken substances with a thick cement is disadvantageous, the object being to bring the surfaces as closely together as possible. As an illustration of a right and a wrong way of mending, we will suppose a plaster of Paris figure broken; the wrong way to mend it is by a thick plate of plaster, which makes, not a joint, but a botch. The right way to mend it, is by means of some well-made carpenter’s glue, which, being absorbed into the porous plaster, leaves merely a film covering the two surfaces, and, if well done, the figure is stronger than elsewhere.

On carefully reading over our article, we find one useful substance has been omitted, namely, what is termed _mastic_ cement, which is used for making a superior coating to inside walls, and which must not be confounded with the _resin mastic_. It is made by mixing twenty parts of well-washed and sifted sharp sand, with two parts of litharge, and one of freshly burned and slaked quick-lime, in fine _dry_ powder. This is made into a putty, by mixing with linseed oil; it sets in a few hours, having the appearance of light stone; and we mention it, as it may frequently be employed with advantage in repairing broken stonework (as stairs) by filling up the missing parts. The employment of Roman cement, plaster, &c., for masonry work, hardly comes within the limits of Domestic Manipulation.

V.

DIVIDING, POWDERING, GRINDING, ETC.

The operations of chopping, powdering, grinding, &c., are so frequently required in cooking, and the other branches of domestic economy, as to render any description of their utility wholly unnecessary; and we may therefore confine ourselves to describing the best means of accomplishing the object desired. Powdering is usually performed by the aid of the pestle and mortar. Most of the works on Cookery recommend the use of a marble mortar; this material is about one of the worst that could be selected for the purpose. In the first place, it is expensive; secondly, it is rapidly corroded, even by the weak acids used for food; thirdly, it is readily stained by oily substances; fourthly, it is absorptive of strong flavours, imparting them readily to the next substance pounded; and lastly, it is brittle, and even if not broken, is not calculated to withstand much wear. By far the best material for the purpose is the Wedgewood ware; mortars made of it are cheaper, cleaner in use, and stronger than those of marble, and are not corroded by acids or alkalies—their pre-eminence is so great, that they are invariably used by druggists.

The act of powdering requires great tact and practice to perform it neatly and rapidly. After the object has been broken into small pieces by blows from the pestle, a grinding action is required; this should at first be given by striking the fragments, not in the centre of the mortar, but towards the side furthest from the operator; the pestle, by this means, grinds over them in its descent to the centre, and much more rapidly accomplishes their division than if mere blows are given. After the object has been divided to a certain extent, blows are entirely useless, and a grinding in circles becomes requisite; if the circle is confined to one part of the mortar, the same portions get rubbed over and over again, the others escaping; this is avoided by constantly and regularly altering the size of the circles. If they are commenced in the centre, they should gradually increase in size until the sides are reached, and then contract again, and so on. By this means, the whole of the powder is brought under the action of the pestle, and the operation is much quicker than if performed at random. One great fault usually committed in powdering, is the endeavour to operate on too large a quantity of material at one time. The operation is much more rapidly conducted if small portions are taken, and if the material is tough, and contains much fibrous matter, the process may be very much shortened by removing those parts which are sufficiently powdered, by sifting from time to time through a sieve. This may be objectionable, however, from the fine powder escaping into the air; in this case, the following contrivance will be found useful:—A cylindrical tea-canister of the requisite size is taken, with a loosely fitting lid, (or, if tight, the lid may be enlarged by four slits being made partly up the sides); a bag of lawn is dropped into the canister, the top being turned over the edge; the powder to be sifted is put in the bag, the lid put on, and, by tapping and shaking, the finest portions pass into the canister without any escaping into the air—a point of very considerable importance where the powder is irritating or expensive.

Various contrivances are constantly had recourse to, in order to render certain substances more readily pulverisable, the contrivance varying very much with the peculiarities of the substance. We will mention a few of these, as they may afford useful suggestions in cases of difficulty. All vegetable, and many mineral substances, are much more readily powdered after having been _thoroughly_ dried; so far is this process carried, that many drugs are dried so as to lose fifteen per cent. of their weight before powdering. In proof of the utility of the drying, let any person try to powder a piece of whiting as it comes from the oilman’s; it will be found to cake together, and be more readily powdered; if dry, however, it powders with the greatest ease. After drying, substances should not be exposed to the air; but, unless they are of such a nature as to be softened by heat, are better operated on while still warm. Flints are more readily powdered by being heated to redness and quenched in cold water; charcoal, for tooth-powder, while still warm from drying. Gum can only be powdered whilst perfectly dry. Camphor, which is with great difficulty powdered alone, yields readily if a drop or two of spirit is poured on it. Substances which clog together and cake under the pestle, are not uncommon; to these it is sometimes requisite to add sand, which may afterwards be separated—this prevents the clogging; but its use is often impracticable. Lime, if required in very fine powder, for dusting over plants to kill slugs, &c., is readily obtained by slaking it, when fresh burned, with _boiling_ water; when, if too much water is not used, it falls into an exceedingly fine powder.

Sal-ammoniac, and some other saline bodies, are most readily powdered by dissolving them in as small a quantity of boiling water as possible, and stirring the solution rapidly as the water is boiled away, or as the solution cools. Before dismissing the pestle and mortar, we may allude to their use in mixing powders together, although a much more ready mode of doing this is with a sieve. Two or more powders stirred together, and passed two or three times through a sieve, are much more intimately mixed, than if rubbed for a long time in a mortar. Metals cannot be divided in the mortar; the most convenient mode of proceeding, if they are fusible under a white heat, is to melt them, and pour them whilst liquid into a pail of water, which should be full to avoid any spluttering, and the hotter the metal, the more filmy the particles. It is scarcely requisite to state, that the metal should be poured in a circle, so as not to collect at one place.

Chopping is usually performed in the kitchen, with a large common knife; but is more speedily done by some of the improved contrivances similar to the following:—The chopping-board should be made of hard wood, with the grain at right angles to the surface of the board, by which it is rendered much more durable than if they are parallel to it. The chopping-knives should be placed at right angles to the handles, and may be of either the following patterns. If a large quantity of material has to be acted on, we would recommend a board as above, not less than three inches thick, and smooth on both sides, so that either may be used, of the requisite size—say eighteen inches or two feet in diameter. On this should stand a loose bottomless tub, to confine the materials, and the whole resting on the floor, should be used with a knife, sufficiently long in the handle to be employed by a person standing erect, and it would be very convenient to have a small cross-bar for the hands, as shown in _Fig. 12_.

Small chopping-knives are sold, consisting of three blades riveted together, and a very convenient one is made by fastening, at convenient distances, a number of flat circular disks, sharpened at the edges, on to a central axis with a handle at each end.

Many substances, such as stale bread, dried herbs, &c., may be very conveniently powdered by rubbing them through a wire sieve, of the requisite degree of fineness. Herbs intended for use in this way, should be dried as rapidly as possible, without being scorched, in small heaps, before the fire; parsley and others done this way, may be powdered, retaining their bright green colour and flavour, both of which are preserved if they are corked tightly in bottles, and kept in a dry, dark cupboard. The use of waxed paper to preserve dried powders in, or for tying them down in jars, or generally as a very good substitute for bladder, will often be found convenient. It is readily made by laying a sheet of smooth stout paper on a warm iron plate, as the top of a kitchen oven; on this place the thin tissue or other paper to be waxed; put a piece of wax on it, and as it melts, rub it over, spreading it evenly. One end of a cork, covered with two thicknesses of linen, answers very well for a rubber. If a hot plate is not at hand, the sheet of paper may be held before the fire, and rubbed over as it warms, with the cut edge of a cake of white wax; but this requires the co-operation of two persons.

VI.

KNOTS, PACKAGES, PARCELS, ETC.

The poet Crabbe, speaking of the writing of the rustics, signing his parish register, says—

“’Tis strange that men
Who guide the plough should fail to guide the pen!
For half a mile the furrows even lie;
For half an inch the letters stand awry.”

A parallel remark might with equal justice be made on the gentler sex, who, after exercising a degree of tact, neatness, and tasteful invention, that the self-styled “lords of the creation” might in vain hope to rival, in the formation of a piece of needlework, knitting, netting, or crochet, are for the most part, totally unable, when it is finished, to tie it up so as to make a decent parcel; ladies’ packages are, in fact, the opprobrium of the sex—the annoyance of all carriers, cads, and coachmen, who have anything to do with their conveyance, and the torment of their owners; the cords are certain to become loose, the knots are sure to slip, except when a slip-knot is requisite, and then it is a fixture! It is in the hope that we may be instrumental in improving this state of things, that we are induced to devote this article to Knots, Packages, Parcels, &c., and we shall at once lay before our fair readers a method of tying a parcel neatly and securely, and at the same time affording facilities of releasing the contents without destroying the string by cutting it away—a too ordinary practice, especially where time is an object.

The most simple purpose for which a knot is required, is the fastening together of two pieces of string or cord: the knot selected for this purpose should possess two important properties—it should be secure from slipping, and of small size. Nothing is more common than to see two cords attached together in a manner similar to that shown in _Fig. 13_. It is scarcely possible to imagine a worse knot; it is large and clumsy, and as the cords do not mutually press each other, it is certain to slip, if pulled with any great force. In striking contrast to this—the worst of all—we place one of the best; namely, the knot usually employed by netters, and which is called by sailors “the sheet-bend.” It is readily made by bending one of the pieces of cord into a loop (_a b_, _Fig. 14_), which is to be held between the finger and thumb on the left hand; the other cord _c_ is passed through the loop from the farther side, then round behind the two legs of the loop, and lastly, under itself, the loose end coming out at _d_. In the smallness of its size, and the firmness with which the various parts grip together, this knot surpasses every other: it can, moreover, be tied readily when one of the pieces, viz., _a_, _b_, is exceedingly short; in common stout twine, less than an inch being sufficient to form the loop. The above method of forming it is the simplest to describe, although not the most rapid in practice; as it may be made in much less time by crossing the two ends of the cord (_a b_, _Fig. 15_) on the tip of the fore-finger of the left hand, and holding them firmly by the left thumb, which covers the crossing; then the part _c_ is to be wound round the thumb in a loop, as shown in the figure, and passed between the two ends, behind _a_ and before _b_; the knot is completed by turning the end _b_ downwards in front of _d_, passing it through the loop, securing it under the left thumb, and tightening the whole by pulling _d_. As formed in this mode, it is more rapidly made than almost any other knot; and, as before stated, it excels all in security and compactness, so firmly do the various turns grip each other, that after having been tightly pulled, it is very difficult to untie; this is the only drawback to its usefulness, and in this respect it is inferior to the reef-knot, _Fig. 16_, which is made in precisely the same manner that a shoestring is tied, only pulling out the ends instead of leaving them as bows. The only precaution necessary in making a reef-knot is, to observe that the two parts of each string are on the same side of the loop; if they are not, the ends (and the bows, if any are formed) are at right angles to the cords; the knot is less secure, and is termed by sailors a granny-knot. Other knots are occasionally used to connect two cords, but it is unnecessary to describe them, as every useful purpose may be answered by those above mentioned.

The binding knot (_Figs. 17_ and _18_) is exceedingly useful in connecting broken sticks, rods, &c., but some difficulty is often experienced in fastening it at the finish; if, however, the string is placed over the part to be united, as shown in _Fig. 17_, and the long end _b_, used to bind around the rod, and finally passed through the loop _a_, as shown in _Fig. 18_, it is readily secured by pulling _d_, when the loop is drawn in, and fastens the end of the cord.

For fastening a cord to any cylindrical object, one of the most useful knots is the clove hitch, which, although exceedingly simple and most easily made, is one of the most puzzling knots to the uninitiated. There are several modes of forming it, the most simple being perhaps as follows:—Make two loops, precisely similar in every respect, as _a_ and _b_, _Fig. 19_, then bring _b_ in front of _a_, so as to make both loops correspond, and pass them over the object to be tied, tightening the ends; if this is properly done, the knot will not slip, although surrounding a tolerably smooth cylindrical object, as a pillar, pole, &c. This knot is employed by surgeons in reducing dislocations of the last joint of the thumb, and by sailors in great part of the standing rigging. The loop which is formed when a cable is passed around a post or tree to secure a vessel near shore is fastened by what sailors term two half hitches, which is simply a clove hitch made by the end of the rope which is passed around the post or tree, and then made to describe the clove hitch around that part of itself which is tightly strained.

From the tying of knots we may pass on to the tying over of bottles, preserves, jars, &c.; the object with which this operation is performed is either to prevent the excess of air or the escape or entrance of moisture; the act itself is so very simple as to require no explanation; but a few words may be said on the choice of material, which should be varied, so as to suit the exigencies of each particular case. When a vessel of spirit is to be tied over, leather is frequently selected—a very erroneous practice, as the vapour of spirit passes readily through that substance, but cannot penetrate bladder, which should be invariably used for the purpose. So effectually is spirit confined by bladder, that when weak spirits are put into bladders or into vessels tied over with bladder, and allowed to remain some time, they are strengthened, as the vapour of the water passes away, that of the spirit being retained.

Bladder, or other animal membranes of the same nature, in a moist and flaccid state, are usually selected for tying over preserves and jams, for which they are well adapted; should it be impracticable to obtain them, the waxed paper described at page 165 is a very good substitute. Many persons place a thin piece of oiled paper in the jar resting on the jam, in addition to tying it down; this assists in excluding air and preventing mouldiness, but we have found a piece of very thin paper moistened with white of egg much more efficacious. The thin sheet-lead used for lining the interior of tea-chests, or stout tin-foil, is very advantageously used in tying down vessels containing specimens of natural history preserved in spirits, as they effectually prevent the escape of the latter for a long series of years. The plan usually pursued is to tie the cork over first with a single bladder, then with the metal, and finally with a second piece of bladder, which is afterwards covered with a coat of black paint.

The tying up of parcels in paper is an operation which is seldom neatly performed by persons whose occupations have not given them great facilities for constant practice. Whether the paper be wrapped round the objects, as is the case usually when it is much larger than sufficient to enclose them, or merely folded over itself, as is done by druggists, who cut the paper to the required size, it is important that the breadth of the paper should be no more than sufficient to enable it to be folded over the ends of the object enclosed, without passing over the opposite side: it is impossible to make a neat or close parcel with paper which is too broad; excess in length may be readily disposed of by wrapping it round; but excess of breadth should be cut away. With regard to turning in the ends, the mode adopted by grocers is the best. The most common cause of failure in parcels is their being badly corded; we will, therefore (however unnecessary the description of so simple a performance may appear to those already acquainted with it), describe the most readily acquired mode of cording.

Let a single knot be made in the end of the cord, which is then passed round the box or parcel. This knotted end is now tied by a single hitch round the middle of the cord (_Fig. 20_) and the whole pulled tight. The cord itself is then carried at right angles round the end of the parcel, and where it crosses the transverse cord on the bottom of the box (_Fig. 21_), it should (if the parcel is heavy, and requires to be firmly secured) be passed _over_ the cross cord, then back underneath it, and pulled tightly, then over itself; lastly, under the cross cord, and on around the other end of the box. When it reaches the top it must be secured by passing it under that part of the cord which runs lengthways (_a_, _Fig. 20_) pulling it very tight, and fastening it by two half hitches round itself. The great cause of parcels becoming loose is the fact of the cord being often fastened to one of the transverse parts (as _b_, _Fig. 20_) instead of the piece running lengthways, and in this case it invariably becomes loose. The description may perhaps be rendered clearer by the aid of the figures, which exhibit the top and bottom of a box corded as described. The cords, however, are shown in a loose state, to allow their arrangements to be perceived more easily.

VII.

ON THE OPERATIONS AFFECTING WATER.

The subject of the Water supply to the Metropolis and other large towns is one of the highest importance to the well-being of the community at large, in whatever point of view it may be regarded—whether as affecting the comfort, the health, or the pocket of the consumer, its influence can scarcely be overrated. To enter, however, into this matter, affecting, as it does, so many varied and conflicting interests, would be to pass beyond the limits set to this series of papers; what remains for us to do is to avail ourselves of the vast amount of scientific knowledge which has been recently brought to bear upon the question, and to cull from it such portions as bear directly upon _Domestic Manipulation_.

The quantity of water for domestic purposes depends mainly upon its degree of hardness or softness; and this in its turn depends almost entirely upon the quantity of lime dissolved in some form or other in the water. In speaking of the quality of water, the term “degree of hardness” is much used; thus we say that the water of the Thames is of fourteen degrees of hardness, that of the Hampstead springs about ten degrees, &c. &c. In these and most other cases the hardness is owing to a certain amount of chalk (carbonate of lime) dissolved, and the degrees of hardness correspond with the number of grains contained in a gallon of water. Thus the Thames water, of fourteen degrees of hardness, has in each gallon fourteen grains of chalk, and the Hampstead ten grains. It is found, upon experiment, that one gallon (weighing 70,000 grains) of _pure_ water will not dissolve more than two grains of chalk, and so acquire two degrees of hardness; and that whenever more is contained in water, the excess is always owing to the presence of carbonic acid gas, which enables it to dissolve a much larger quantity. The practical part of our subject depends on this fact; for if by any means we can get rid of the carbonic acid, the dissolved chalk is necessarily precipitated, and the hard water, unfit for culinary and domestic purposes, becomes soft, and well adapted to both these uses. Carbonic acid is in part expelled from water by heating it to the boiling point: a still larger quantity is got rid of after boiling for some few minutes, and nearly every trace disappears at the end of half an hour; and just in proportion as the carbonic acid gas is expelled, so does the chalk fall, rendering the water in the first instance turbid, and becoming deposited on the interior surface of kettles, where it forms the well-known rock or _fur_.

It has been found that water of fourteen degrees of hardness lost two degrees when merely made boil; boiling for five minutes reduced the hardness to six degrees; and for a quarter of an hour, to little more than four degrees. The practical application of this knowledge needs scarcely to be pointed out. Whenever a soft water is required, boil for several minutes before using. In making tea, for instance, the economy and general superiority of soft water is well known. Those, however, who use Thames water, just made to boil, employ a water of upwards of eleven degrees of hardness: those who boil for five minutes, diminish the hardness of the water by nearly one-half; and by boiling for a quarter of an hour, it can be lessened to one-third. This circumstance is one of those that prove how great a substratum of truth there is at the bottom of most popular notions. How many a young gentleman, with a smattering of science just enough to inform him that water gets no hotter however long or violently it is boiled, has laughed at his grandmother’s antiquated notions, because she requested that the water might be made to boil thoroughly before the tea was made: the old lady could give no very satisfactory explanation of her prejudice, yet it was not the less a correct one.

Before going further in this matter, it may be stated that there are some waters in which the lime is dissolved in the form of gypsum (sulphate of lime); in these, which fortunately are rare, the hardness is of a permanent character, and cannot be lessened by boiling. Tea made under such circumstances may be improved, either by the addition of a _very small_ quantity of carbonate of soda, or the tea should be kept soaking for half an hour, under such circumstances as will retain the heat. This latter is the plan followed in Greenwich Hospital, where they use a well water of nineteen degrees of permanent hardness.

In washing, the use of hard water is, as is well known, extremely prejudicial. The explanation is exceedingly simple: every degree of hardness in a gallon of water destroys ten grains of soap; and by following out the calculation, it will be found that 100 gallons of unboiled Thames water waste exactly two pounds of soap before any approach to a lather can be made. Now what is the remedy for this evil? Simply to boil the water some time before use; one quarter of an hour’s boiling will reduce the waste of soap from two pounds to ten ounces; and half an hour’s boiling will still further lessen it to six ounces; but no amount of boiling will make Thames water equal to rain water, which is without hardness.

There is one practical matter of great importance to which we wish to draw the attention of all concerned; it is the effect of boiling linen in hard water. If clothes are put into cold water, and then boiled, the precipitation of chalk (which has been so often alluded to) takes place on the clothes, and whatever colouring matter exists in the water goes down with the chalk, and also becomes attached to the linen, rendering it of that disagreeable and unremovable dirty hue which is so characteristic of certain laundries. If boiling is absolutely requisite for white fabrics, it should be done in water which has been boiled half an hour, allowed to stand, and then poured off from the sediment; otherwise, from the immediate precipitation of the chalk, the dirt is boiled in and thoroughly fixed to the fabric. A moment’s consideration will convince any one that a deposit similar to the _fur_ in a tea-kettle cannot be expected to improve the appearance of white linen. Where clear rain water can be obtained, there is no objection to the boiling of clothes in it, as, being absolutely free from lime, no precipitation can take place. The use of soda in softening water employed in washing, is well known; but the remedy is not without its own evil: it weakens the fibre of the cloth, and unless it is much more thoroughly removed by rinsing than is usually the case, it occasions a very permanent yellow tinge when the cloth is heated.

VIII.

BOILING, STEWING, ETC.

From our last article on the properties of hard and soft water, we pass, by a natural transition, to the employment of that liquid in the culinary operations above named. In practice, nothing can at first sight appear more simple than the operation of boiling, whether it be confined to the mere heating of a liquid, or extended to the preparation of an article of food; yet it is one which involves chemical principles of a very high order, and which is by no means so simple a matter as it may be regarded at a cursory glance.