Cooley's Cyclopaedia of Practical Receipts Volume Ii Part 42

=Magnesium, Sulphate of.= MgSO_{4}, 7 Aq. _Syn._ EPSOM SALT, MAGNESIae SULPHAS (B. P. Ph. L. E. & D.), SAL EPSOMENSIS, L. This compound was originally extracted from the saline springs of Epsom, Surrey, by Dr Grew, in 1695. It is now exclusively prepared on the large scale, and from either magnesian limestone or the residual liquor of the sea-salt works.

_Prep._ 1. From dolomite or magnesian limestone.--_a._ The mineral, broken into fragments, is heated with a sufficient quant.i.ty of dilute sulphuric acid to convert its carbonates into sulphates; the sulphate of magnesium is washed out of the ma.s.s with hot water, and the solution, after defecation, is evaporated and crystallised.

_b._ The 'limestone,' either simply broken into fragments or else calcined (burnt), and its const.i.tuents quicklime and oxide magnesium converted into hydrates by sprinkling (slaking) it with water, is treated with a sufficient quant.i.ty of dilute hydrochloric acid to dissolve out all the calcium hydrate without touching the magnesium hydrate; the residuum of the latter, after being washed and drained, is dissolved in dilute sulphuric acid, and crystallised as before.

2. From bittern.--_a._ The residual liquor or mother-water of sea-salt is boiled for some hours in the pans which are used during the summer for the concentration of brine; the saline solution is then skimmed and decanted from some common salt which has been deposited, after which it is concentrated by evaporation, and, finally, run into wooden coolers; in about 36 hours, 1-8th part of Epsom salts usually crystallises out. This is called 'singles.' By re-dissolving this in water, and re-crystallisation, 'doubles,' or Epsom salts fit for the market, are obtained. A second crop of crystals may be procured by adding sulphuric acid to the mother-liquor, and re-concentrating the solution, but this is seldom had recourse to in England. Bittern yields fully 5 parts of sulphate of magnesia for every 100 parts of common salt that has been previously obtained from it.

_b._ A concentrated solution of sulphate of sodium is added to bittern, in equivalent proportion to that of the chloride of magnesium in it, and the mixed solution is evaporated at the temperature of 122 Fahr. (Ure); cubical crystals of common salt are deposited as the evaporation proceeds, after which, by further concentration and repose, regular crystals of sulphate of magnesia are obtained.

_c._ A sufficient quant.i.ty of calcined and slaked magnesian limestone is boiled in bittern to decompose the magnesium salts, and the liquid is evaporated, &c., as before. This is a very economical process.

_Prop._ Small acicular crystals, or (by careful crystallisation) large four-sided rhombic prisms; colourless; odourless, transparent; slightly efflorescent; extremely bitter and nauseous; when heated, it fuses in its water of crystallisation, the larger portion of which readily pa.s.ses off, but one equivalent of water is energetically retained; at a high temperature it runs into a species of white enamel; it dissolves in its own weight of cold water, and in 3-4ths of that quant.i.ty of boiling water; it is insoluble in both alcohol and ether. Sp. gr. 166.

_Pur._ Sulphate of magnesium is soluble in an equal weight of water at 60 Fahr., by which it may be distinguished from sulphate of sodium, which is much more soluble.

An aqueous solution in the cold is not precipitated by oxalate of ammonium. The precipitate given by carbonate of sodium from a solution of 100 gr. should, after well washing and heating to redness, weigh 1626 gr.

(B. P.)

Digested in alcohol, the filtered liquid does not yield a precipitate with nitrate of silver nor burn with a yellow flame, and evaporates without residue. "Not deliquescent in the air." (Ph. L.) 100 gr. of the pure crystallised sulphate yields 16-1/4 gr. of calcined magnesium oxide.

(Pereira.) 10 gr., dissolved in 1 fl. oz. of water, and treated with a solution of carbonate of ammonium, are not entirely precipitated by 280 minims of solution of phosphate of sodium. (Ph. E.)

_Uses, &c._ Sulphate of magnesium is an excellent cooling purgative, and sometimes proves diuretic and diaph.o.r.etic.--_Dose_, 1 dr. to 1 oz., as a purgative, or an antidote in poisoning by lead. Large doses should be avoided. Instances are on record of their having proved fatal. Dr Christison mentions the case of a boy 10 years old who swallowed 2 oz. of salts, and died within 10 minutes. The best antidote is an emetic. A small quant.i.ty of Epsom salts, largely diluted with water (as a drachm to 1/2 pint or 3/4 pint), will usually purge as much as the common dose. This increase of power has been shown by Liebig to result rather from the quant.i.ty of water than the salt. Pure water is greedily taken up by the absorbents; but water holding in solution saline matter is rejected by those vessels, and consequently pa.s.ses off by the intestines.

_Obs._ Oxalic acid has occasionally been mistaken for Epsom salt, with fatal results. They may be readily distinguished from each other by the following characteristics:--

EPSOM SALT. OXALIC ACID.

Tastes extremely bitter Tastes extremely sour.

and nauseous. Volatilises when heated Does not volatilise on platinum foil.

when heated on platinum foil. Does not Produces milkiness produce milkiness when dissolved in when dissolved in _hard_ water.

_hard_ water.

=Magnesium, Tar'trate of.= _Syn._ MAGNESIae TARTRAS, MAGNESIA TARTARICA, L.

_Prep._ By saturating a solution of tartaric acid with carbonate of magnesium, and gently evaporating to dryness. It is only very slightly soluble in water.--_Dose_, 20 to 60 gr., or more; in painful chronic maladies of the spleen. (Pereira, ex Radmacher.) The effervescing tartrate of magnesium, commonly sold under the name citrate, has already been noticed.

=Magnesium and Potas'sium, Tartrate of.= _Syn._ POTa.s.sIO-TARTRATE OF MAGNESIA; MAGNESIae POTa.s.sIO-TARTRAS, M. ET POTa.s.sae TARTRAS, L. _Prep._ From acid tartrate of pota.s.sium (in powder), 7 parts; carbonate of magnesium, 2 parts; water, 165 parts; boiled until the solution is complete, and then evaporated and crystallised. A mild aperient.--_Dose_, 1 to 5 dr.; in scurvy, &c.

=MAG'NET.= _Syn._ MAGNES, L. Besides its application to the loadstone, this name was formerly given to several compounds used in medicine.--a.r.s.eNICAL MAGNET (MAGNES a.r.s.eNICALIS), a substance once used as a caustic, consisted of common antimony, sulphur, and a.r.s.enious acid, fused together until they formed a sort of gla.s.s. MAGNES EPILEPSIae was native cinnabar.

=MAHOG'ANY.= This is the wood of _Swietenia Mahogoni_ (Linn.), a native of the hotter parts of the new world. It is chiefly imported from Honduras and Cuba. The extract is astringent, and has been used in tanning, and as a subst.i.tute for cinchona bark. The wood is chiefly employed for furniture and ornamental purposes, and, occasionally, in ship-building.

Imitations of mahogany are made by staining the surface of the inferior woods by one or other of the following methods:

1. Warm the wood by the fire, then wash it over with aquafortis, let it stand 24 hours to dry, and polish it with linseed oil reddened by digesting alkanet root in it; or, instead of the latter, give the wood a coat of varnish, or French polish which has been tinged of a mahogany colour with a little aloes and annotta.

2. Socotrine aloes, 1 oz.; dragon's blood, 1/2 oz.; rectified spirit, 1 pint; dissolve, and apply 2 or 3 coats to the surface of the wood, previously well smoothed and polished; lastly, finish it off with wax or oil tinged with alkanet root.

3. Logwood, 2 oz.; madder, 8 oz.; fustic, 1 oz.; water, 1 gall.; boil 2 hours, and apply it several times to the wood boiling hot; when dry, slightly brush it over with a solution of pearlash, 1 oz.; in water, 1 quart; dry, and polish as before.

4. As the last, but using a decoction of logwood, 1 lb., in water, 5 pints. The tint may be brightened by adding a little vinegar or oxalic acid, and darkened by a few grains of copperas.

Stains and spots may be taken out of mahogany furniture with a little aquafortis or oxalic acid and water, by rubbing the part with the liquid by means of a cork till the colour is restored; observing afterwards to well wash the wood with water, and to dry it and polish it as before.

=MAIZE.= _Syn._ INDIAN CORN. The seeds of _Zea Mays_ (Linn.). Like the other corn plants, it belongs to the Gra.s.s family (_Graminaceae_), and has alb.u.minous grains sufficiently large and farinaceous to be ground into flour.

Maize is extremely nutritious, and although it is poorer in alb.u.menoid matters than wheat, it is, of all the cereal grains, the richest in fatty oil, of which it contains about 9%. (Dumas and Payen.) It is remarkable for its fattening quality on animals, but is apt to excite slight diarrha in those unaccustomed to its use. Its meal is the 'POLENTA' of the shops. The peculiar starch prepared from it is known as 'CORN FLOUR,'

In America the young ears are roasted and boiled for food.

The centesimal composition of maize is as follows:--Flesh formers (alb.u.menoid bodies), 99; heat and fat formers (starch, dextrin, and fat), 712, fibre, 40; ash, 14; water, 135.

Letheby says of maize: "The grain is said to cause disease when eaten for a long time, and without other meal--the symptoms being a scaly eruption upon the hands, great prostration of the vital powers, and death after a year or so, with extreme emaciation.

These effects have been frequently observed amongst the peasants of Italy, who use the meal as their chief food, but I am not aware of any such effects having been seen in Ireland, where it is often the only article of diet for months together."

Millions of bushels are grown every year in the United States of America, and large quant.i.ties are continually imported into England, where it is held in high esteem by cattle breeders, it being much cheaper than many of our home-grown productions. It is occasionally given to horses as a subst.i.tute for oats.

=MALAG'MA.= In _pharmacy_, a poultice or emollient application.

=MA'LIC ACID.= H_{3}C_{4}H_{3}O_{5}. _Syn._ ACIDUM MALIc.u.m, L. This acid exists in the juice of many fruits and plants, either alone or a.s.sociated with other acids, or with pota.s.sa or lime. In the juice of the garden rhubarb it exists in great abundance, being a.s.sociated with acid oxalate of pota.s.sa.

_Prep._ (Everitt.) The stalks of common garden rhubarb are peeled, and ground or grated to a pulp, which is subjected to pressure; the juice is heated to the boiling point, neutralised with carbonate of pota.s.sa, mixed with acetate of lime, and the insoluble oxalate of lime which falls is removed by filtration; to the clear and nearly colourless liquid, solution of acetate of lead is next added as long as a precipitate ('malate of lead') continues to form; this is collected on a filter, washed, diffused through water, and decomposed by sulphuric acid, avoiding excess, the last portion of lead being thrown down by a stream of sulphuretted hydrogen; the filtered liquid is, lastly, carefully evaporated to the consistence of a syrup, and left in a dry atmosphere until it becomes converted into a solid and somewhat crystalline ma.s.s of malic acid. If perfectly pure malic acid is required, the malate of lead must be crystallised before decomposing it with sulphuretted hydrogen. _Prod._ 20,000 gr. of the peeled stalks yield 12,500 gr. of juice, of which one imperial gallon contains 11,139-1/4 gr. of dry malic acid.

_Obs._ By a similar process malic acid may be prepared from the juice of thee berries of the mountain ash (_Sorbus aucuparia_), just when they commence to ripen, or from the juice of apples, pears, &c.

_Prop., &c._ Malic acid is slightly deliquescent, very soluble in water, soluble in alcohol, and has a pleasant acidulous taste. The aqueous infusion soon gets mouldy by keeping. When kept fused for some time at a low heat, it is converted into fumaric acid; and when quickly distilled, it yields maleic acid, while fumaric acid is left in the retort. With the bases malic acid forms salts called malates. Of these the acid malate of ammonia is in large, beautiful crystals; malate of lead is insoluble in cold water, but dissolves in warm dilute acid, from which it separates on cooling in brilliant silvery crystals; acid malate of lime also forms very beautiful crystals, freely soluble in water; neutral malate of lime is only sparingly soluble in water; the first is obtained by dissolving the latter in hot dilute nitric acid, and allowing the solution to cool very slowly.

=MALLEABIL'ITY.= The peculiar property of metals which renders them capable of extension under the hammer.

=MALT.= _Syn._ BINA, BYNE, BRASIUM, MALTUM, L. The name given to different kinds of grain, such as barley, bere or bigg, oats, rye, maize, &c., which have become sweet, from the conversion of a portion of their starch into sugar, in consequence of incipient germination artificially produced.

Barley is the grain usually employed for this purpose.

_Var._ Independently of variations of quality, or of the grain from which it is formed, malt is distinguished into varieties depending on the heat of the kiln employed for its desiccation. When dried at a temperature ranging between 90 and 120 Fahr., it const.i.tutes 'PALE MALT,' when all the moisture has exhaled, and the heat is raised to from 125 to 135, 'YELLOW,' or 'PALE AMBER MALT,' is formed; when the heat ranges between 140 and 160, the product receives the name of 'AMBER MALT,' at 160 to 180, 'AMBER-BROWN,' or 'PALE BROWN MALT,' is obtained. ROASTED, PATENT, or BLACK MALT, and CRYSTALLISED MALT, are prepared by a process similar to that of roasting coffee. The malt is placed in sheet-iron cylinders over a strong fire, and the cylinders made to revolve at the rate of about 20 revolutions per minute if roasted malt is required, or 120 for crystallised malt. In the former case the finished malt has a dark brown colour; in the latter, the interior of the grain becomes dark brown, whilst the husk a.s.sumes a pale amber hue. The temperature must never exceed 420, or the malt will become entirely carbonised.

_Qual._ Good malt has an agreeable smell and a sweet taste. It is friable, and when broken discloses a floury kernel. Its husk is thin, clean, and unshrivelled in appearance, and the acrospire is seen extending up the back of the grain, beneath the skin. The admixture of unmalted with malted grain may be discovered, and roughly estimated, by throwing a little into water, malt floats on water, but barley sinks in it. The only certain method, however, of determining the value of malt is to ascertain the amount of soluble matter which it contains, by direct experiment. This varies from 62 to 70%, and for good malt is never less than 66 to 67%. If we a.s.sume the quarter of malt at 324 lbs., and the average quant.i.ty of soluble matter at 66%, then the total weight of soluble matter will be fully 213-3/4 lbs. per quarter; but as this, "in taking on the form of gum and sugar" during the process of mashing, "chemically combines with the elements of water, so the extract, if evaporated to dryness, would reach very nearly 231 lbs.; and this reduced to the basis of a barrel of 36 gallons, becomes in the language of the brewer, 87 lbs. per barrel, which, however, merely means that the wort from a quarter of malt, if evaporated down to the bulk of a barrel of 36 gallons, would weigh 87 lbs. more than a barrel of water." (Ure.)

_a.s.say._ 1. A small quant.i.ty of the sample being ground in a coffee or pepper mill, 100 gr. are accurately weighed, and dried by exposure for about 1 hour at the temperature of boiling water. The loss in weight, in grains, indicates the quant.i.ty of moisture per cent. This, in good malt, should not exceed 6-1/2 gr.

2. A second 100 gr. is taken and stirred up with about 1/2 pint of cold water; the mixture is then exposed to the heat of boiling water for about 40 minutes; after which it is thrown on a weighed filter, and the undissolved portion washed with a little hot water; the undissolved portion, with the filter, is then dried at 212 Fahr., and weighed. The loss in weight, less the percentage of moisture last found, taken in grains, gives the percentage of soluble matter. This should not be less than 66 gr. The same result will be arrived at by evaporating the filtered liquid and 'washings' to dryness, and weighing the residuum.

3. A third 100 gr. is taken and mashed with about 1/2 pint of water at 160 Fahr., for 2 or 3 hours; the liquid is then drained off, the residue gently squeezed, and the strained liquid evaporated to dryness, as before, and weighed. This gives the percentage of saccharine matter, and should not be less than about 71 gr., taking the above average of malt as the standard of calculation.

_Uses, &c._ Malt is chiefly employed in the arts of brewing and distillation. Both roasted and crystallised malt are merely used to colour the worts produced from pale malt. 1 lb. of roasted malt, mashed with 79 lbs. of pale malt, imparts to the liquor the colour and flavour of 'porter.' The paler varieties of malt contain the largest quant.i.ty of saccharine matter. After the malt has been kiln-dried, the rootlets may be removed by means of a sieve. Before malt is mashed for beer it must be broken up, and the law requires that it be bruised or crushed by smooth metal rollers, and not ground by millstones. It has also been proposed to employ malt, instead of raw grain, for fattening domestic animals, and as food for their young and those in a sickly state. Infusion of malt (sweet wort, malt tea) is laxative, and has been recommended as an antis...o...b..tic and tonic. It has been given with great advantage in scurvy; but for this purpose good, well-hopped, mild beer is equally serviceable and more agreeable. See BREWING, DISTILLATION, FERMENTATION, &c.

=MALT LIQ'UORS.= The qualities of ale, beer, and porter, as beverages, the detection of their adulteration, and the methods of preparing them, are described under their respective names and in the article upon 'BREWING'; the present article will, therefore, be confined to a short notice of the cellar management, and the diseases of malt liquors generally.

AGE. The appearance and flavour to which this term is applied can, of course, be only given to the liquor by properly storing it for a sufficient time. Fraudulent brewers and publicans, however, frequently add a little oil of vitriol (diluted with water) to new beer, by which it a.s.sumes the character of an inferior liquor of the cla.s.s 1 or 2 years old.

Copperas, alum, sliced onions, Seville oranges, and cuc.u.mbers, are also frequently employed by brewers for the same purpose.

BOTTLING. Clean, sweet, and dry bottles, and sound and good corks, should be had in readiness. The liquor to be bottled should be perfectly clear; and if it be not so, it must be submitted to the operation of 'fining.'