Chapter LVI: Part 2 (17)

3. (ADRIANOPLE RED, TURKEY R.) This commences with cleansing or scouring the goods by alkaline baths, after which they are steeped in oily liquors brought to a creamy state by a little carbonate of soda; a bath of sheep’s dung is next often used as an intermediate or secondary steep; the oleaginous bath, and the operation of removing the superfluous or loosely adhering oil with an alkaline bath, is repeated two or three times, due care being taken to dry the goods thoroughly after each distinct process; then follow the distinct operations of galling, aluming, maddering, and brightening, the last for removing the dun-coloured principle, by boiling at an elevated temperature with alkaline liquids and soap; the whole is generally concluded with treatment by spirit of tin. In this way are given the most brilliant reds on cotton.

_Obs._ Wool takes from half its weight of madder to an equal weight to dye it red; cotton and linen take rather less. On account of the comparative insolubility of the colouring matter of madder, this dye-stuff must be boiled along with the goods to be dyed, and not removed from the decoction, as is the practice in using many other articles. Other dye-stuffs are frequently added to the madder bath, to vary the shades of colour. Decoction of fustic, weld, logwood, quercitron, &c., are often thus employed, the mordants being modified accordingly. By adding bran to the madder bath the colour is said to be rendered much lighter, and of a more agreeable tint.

=RED GUM.= A slight eruptive disease of infancy, occasioned by teething, and, less frequently, by irritation from rough flannel worn next to the skin. See STROPHULUS.

=RED LAV′ENDER.= See TINCTURE OF LAVENDER (Compound).

=RED LIQ′UOR.= The crude solution of acetate or sulpho-acetate of alumina employed in calico printing. It is generally prepared by mixing crude sulphate of alumina with about an equal weight of crude pyrolignite of lime, both being in the state of solution.

=RED PIG′MENTS.= The preparation of the principal red pigments are described under their respective names. The following list includes most of the reds in use:——

=Arme′nian Bole.= _Syn._ BOLE ARMENIAN; BOLUS ARMENIÆ, L. Formerly imported from Armenia, Portugal, Tuscany, &c.; now generally made by grinding together a mixture of whiting, red oxide of iron, and red ochre, in nearly equal proportions.

=Red, Brown.= A factitious mixture of red oxide of iron and red ochre, in variable proportions.

=Car′mine.=

=Carmina′ted Lake.=

=Red Chrome.= _Syn._ DICHROMATE OF LEAD, RED CHROMATE OF L.; PLUMBI DICHROMAS, P. CHROMUS RUBRUM, L. _Prep._ 1. Boil pure carbonate of lead with chromate of potassa, in excess, until it assumes a proper colour; then wash it well with pure water, and dry it in the shade.

2. Boil neutral chromate of lead with a little water of ammonia or lime water.

3. (Liebig and Wöhler.) Fuse saltpetre at a low red heat in a Hessian crucible, and throw in chromate of lead (pure chrome yellow), by small portions at a time, as long as a strong ebullition follows upon each addition of the pigment, observing to stir the mixture frequently with a glass rod; after repose for a minute or two, pour off the fluid part, and, as soon as the solid residuum is cold, wash it with water, and dry it by a gentle heat.

_Obs._ Great care must be taken, in conducting the last process, not to employ too much heat, nor to allow the saline matter to stand long over the newly formed chrome-red, as the colour is thus apt to change to a brown or orange. When well managed the product has a crystalline texture, and so beautiful a red colour that it vies with native cinnabar. The liquid poured from the crucible is reserved for manufacturing chrome yellow.

=Red, In′dian.= _Syn._ PURPLE OCHRE; OCHRA PURPUREA PERSICA, TERRA PERSICA, L. This is a native production, brought from Ormus. A factitious article is prepared by calcining a mixture of colcothar and red ochre.

=Lakes= (Various).

=Red, Light.= From yellow ochre, by careful calcination. It works well with both oil and water, and produces an admirable flesh-colour by admixture with pure white. All the ochres, both red and yellow, are darkened by heat.

=Red Or′ange.= _Syn._ SANDIX. Obtained from white lead by calcination. Very bright.

=Real′gar.= Bisulphide of arsenic.

=Red Bole.= See ARMENIAN and VENETIAN BOLE. (Ochres.)

=Red Chalk.= A clay iron ore, much used for pencils and crayons, and, when ground, also for paints.

=Red Lead.= _Syn._ MINIUM. The finest red lead is prepared by exposing ground and elutriated massicott, or dross of lend, in shallow iron trays (about 12 inches square, and about 4 or 5 inches deep), piled up on the hearth of a reverberatory furnace, to a heat of about 600 to 650° Fahr., with occasional stirring, until it acquires the proper colour. The furnace employed for the preparation of massicot during the day usually possesses sufficient residuary heat during the night for this process, by which fuel is saved. Lead for the above purpose should be quite free from copper and iron.

=Red O′chre.= A natural product abounding on the Mendip hills.

=Red Or′piment.= _Syn._ RED ARSENIC. Tersulphide of arsenic.

=Red Vene′tian.= _Syn._ BOLUS VENETA, L. A species of ochre, brought from Italy.

=Rose Pink.= This is whiting coloured with a decoction of Brazil wood to which a little pearlash has been added. A very pretty colour, but it does not stand. It is always kept in a damp state. The colour may be varied by substituting alum for pearlash, or by the addition of a little spirits of tin.

=Vermil′ion.= (See under that word.)

=REDUC′TION.= _Syn._ REVIVIFICATION. A term in its fullest sense applied to any operation by which a substance is restored to its neutral state; but now generally restricted, in chemistry, to the abstraction of oxygen, and hence frequently termed deoxidation or deoxidisement. This change is operated by either heating the substance in contact with carbon or hydrogen, or in exposing it to the action of some other body having a powerful affinity for oxygen. See POTASSIUM, &c.

=REFI′′NING.= A term employed in commercial chemistry and metallurgy synonymously with purification. The separation of the precious metals from those of less value, as in the operation of parting, constitutes the business of the ‘refiner.’ See GOLD, SILVER, &c.

=REFRAC′TION (of Light).= The deviation of a ray of light from its original path on entering a medium of a different density or power. For the practical application of this property, see GEMS.

=REFRI′′GERANTS.= Medicines or agents which tend to lessen the animal temperature without causing any marked diminution of sensibility or nervous energy. Among internal refrigerants cold water, weak acidulous drinks, and saline aperients, are those which are probably the best known and the most useful. Among external refrigerants are cold water, evaporating lotions, weak solutions of subacetate of lead, &c.

=REFRIGERA′TION.= The abatement of heat; the act or operation of cooling.

Among the purposes to which refrigeratory processes are applied in the arts, the principal are——the condensation of vapours——the cooling of liquids——the congelation of water, and——the production of extreme degrees of cold in chemical operations. The first of these is referred to under the heads DISTILLATION, STILL, &c., and the second under WORT. It is, therefore, only necessary to notice here the third and fourth applications of cold, artificially produced, above referred to.

The refrigeratory processes at present employed depend upon the greater capacity for heat which the same body possesses as its density lessens, or its attenuation increases; as exhibited in the sudden liquefaction of solids, the rapid evaporation of liquids, and the almost instantaneous return of atmospheric air, or other gaseous body, from a highly condensed state to its normal condition. The loss of sensible heat in the first example is the basis of the various processes of producing cold by what are commonly called ‘FREEZING-’ or ‘FRIGORIFIC-MIXTURES,’ all of which act upon the principle of liquefying solid substances without supplying heat. The caloric of liquidity being in these cases derived from that previously existing in the solid itself in a sensible state, the temperature must necessarily fall. The degree of cold produced depends upon the quantity of heat which is thus diffused through a larger mass, or which, as it were, disappears; and this is dependent on the quantity of solid matter liquefied, and the rapidity of the liquefaction. Saline compounds are the substances most frequently employed for this purpose, and those which have the greatest affinity for water, and thus liquefy the most rapidly, produce the greatest degree of cold. Similar changes occur during the evaporation of liquids. When heat passes from the sensible to the insensible state, as in the formation of vapour, cold is generated. This may be shown by pouring a few drops of ether or rectified spirit on the palm of the hand, when a strong sensation of cold is experienced. A still more familiar illustration of this fact is exhibited in the rapidity with which the animal body loses heat when enveloped in damp or wet clothing. The evaporation of water produces a degree of cold which is greater than that of other liquids, in exact proportion as the insensible or latent heat of its vapour exceeds theirs. In the attenuation or rarefaction of gases similar phenomena occur.

It has been found that evaporation proceeds much more rapidly from the surface of fluids in a vacuum than in the atmosphere. Water may be easily frozen by introducing a surface of sulphuric acid under the receiver of an air-pump, over which is placed a capsule filled with water, so that the vapour arising from the latter may be immediately absorbed by the former. After a few strokes of the piston the water is converted into a solid cake of ice. The acid operates by absorbing the aqueous vapours as soon as generated, and thus maintaining the integrity of the vacuum. Professor Leslie found that, when air is thus rarified 250 times, the surface of evaporation was cooled down 120° in winter; and when only 50 times, a depression of 80° or even 100° took place. “Sulphuric acid is capable of congealing more than 20 times its weight of water before it has imbibed nearly its own bulk of that liquid, or has lost about 1/8th of its refrigerating power.” (Ure.) Sulphuric acid, which has become diluted in this way, may be reconcentrated by heat. Any substance having a great tendency to absorb moisture may be substituted for the sulphuric acid. Fused chloride of calcium, quicklime, nitrate of magnesium, chloride of zinc, and oatmeal (dried nearly to brownness before a common fire), have been used for this purpose. Again, instead of employing an air-pump, a vacuum may be produced by the agency of steam, afterwards condensed by the affusion of cold water.

A pleasing philosophical toy, illustrative of the evaporative power of a vacuum, is the ‘CRYOPHORUS,’ or ‘FROST-BEARER,’ of Dr Wollaston. This instrument consists of two small glass globes, united by a tube, one of which is partly filled with water. The whole apparatus is perfectly free from air, and is, consequently, filled with attenuated aqueous vapours. No sooner is the pressure removed as by plunging the empty ball into a freezing mixture (which condenses the vapour), than rapid evaporation commences, and the water in the other ball is frozen in two or three minutes.

Even in hot climates ice may be produced under favorable circumstances by evaporation. On the open plains, near Calcutta, this is effected by exposing a thin stratum of water to the atmosphere, during the fine clear nights of December, January, and February. The pans are made of porous earthenware, and water is poured in to the depth of about 1-1/2 inch. A large number of these vessels are arranged in an excavation in the ground, 30 or 40 feet square and 2 feet deep, the bottom of which is covered, to the depth of 10 or 12 inches, with sugar canes or the stalks of Indian corn. At sunrise the pans are visited, the ice separated from the water, and packed as tight as possible in a deep cavity or pit, well screened from the heat.

Several machines have recently been invented by which water is frozen in large quantities by exposure to condensed air in the act of its subsequent expansion. They are worked by either hand or steam power. The refrigerating apparatus invented by Mr Kirk, of the Bathgate Paraffin Works, acts on this principle; and it does its work so efficiently that it produces a cooling effect equivalent to two tons of ice every twenty-four hours, at a very small expenditure of fuel. A small model worked by hand will readily freeze mercury. Kirk’s apparatus is used at Bathgate to cause the crystallisation of solid paraffin from the heavy paraffin oils. Formerly, a machine, acting by the evaporation of ether, was employed for the same purpose.

For the production of an extremely low temperature, such as is required for the liquefaction of some gases, Faraday employed solid carbonic acid mixed with a little ether.

In the production of ice or an extreme degree of cold, by saline mixtures, the salts should be in the crystallised state, and as rich as possible in water, but without being in the least damp. They should also be coarsely pulverised at the time of using them, and should not be mixed until immediately before throwing them into the liquid ingredients. The mixture should be made in a thick vessel, well clothed, to prevent the accession of external heat; and the substance to be acted on should be contained in a very thin vessel, so as to expose it more fully to the action of the mixture. On the large scale, a vessel called a ‘FREEZING POT’ or ‘SABOTIÈRE’ is commonly employed. The following table, though founded on experiments made more than 50 years ago by Mr Walker, gives full and accurate information on the subject of freezing mixtures:——

Table _exhibiting a few of the most useful_
FRIGORIFIC MIXTURES. _Drawn up from actual
experiments performed by_ MR WALKER.

+----------------------------------------+------------------------+---------------+
| | | Deg. of cold |
| Ingredients. | Thermometer sinks. | produced. |
+----------------------------------------+------------------------+---------------+
| Snow or pounded ice 2 parts { From any | |
| Chloride of sodium 1 ” { temperature. to -5° | —— |
+----------------------------------------{------------------------+---------------+
| Snow or pounded ice 5 ” { From any | |
| Chloride of sodium 2 ” { temperature. to -12° | —— |
| Sal ammoniac 1 ” { | |
+----------------------------------------{------------------------+---------------+
| Snow or pounded ice 12 ” { From any | |
| Chloride of sodium 5 ” { temperature to -25° | —— |
| Nitrate of ammonia 5 ” { | |
+-----------------------------------------------------------------+---------------+
| Snow 8 ” | |
| Hydrochloric From +32° to -27° | 59° |
| acid (_concentrated_) 5 ” | |
+-----------------------------------------------------------------+---------------+
| Snow 2 ” | |
| Crystallised chloride From +32° to -50° | 82° |
| of calcium 3 ” | |
+-----------------------------------------------------------------+---------------+
| Sal ammoniac 5 ” | |
| Nitrate of potassa 5 ” From +50° to +10° | 40° |
| Water 16 ” | |
+-----------------------------------------------------------------+---------------+
| Nitrate of ammonia 1 ” From +50° to +4° | 46° |
| Water 1 ” | |
+-----------------------------------------------------------------+---------------+
| Nitrate of ammonia 1 ” | |
| Carbonate of soda 1 ” From +50° to +7° | 57° |
| Water 1 ” | |
+-----------------------------------------------------------------+---------------+
| Phosphate of soda 9 ” | |
| Nitrate of ammonia 6 ” From +50° to -21° | 71° |
| Diluted nitrous acid[135]4 ” | |
+-----------------------------------------------------------------+---------------+
| Sulphate of soda 8 ” From +50° to 0° | 50° |
| Hydrochloric acid 5 ” | |
+-----------------------------------------------------------------+---------------+
| Snow 3 ” From 0° to -46° | 46° |
| Diluted nitrous acid[135]2 ” | |
+-----------------------------------------------------------------+---------------+
| Snow 2 ” | |
| Sulphuric acid[136] 1 ” From -20° to -60° | 40° |
| Water 1 ” | |
+-----------------------------------------------------------------+---------------+
| Snow 1 ” | |
| Crystallised chloride From 0° to -66° | 66° |
| of calcium 2 ” | |
+-----------------------------------------------------------------+---------------+
| Snow 1 ” | |
| Crystallised chloride From -40° to -73° | 33° |
| of calcium 3 ” | |
+-----------------------------------------------------------------+---------------+
| Snow 8 ” | |
| Sulphuric acid 5 ” From -68° to -91° | 23° |
| Water 5 ” | |
+-----------------------------------------------------------------+---------------+

[Footnote 135: Fuming “nitrous acid,” 2 parts; water, 1 part; by weight.]

[Footnote 136: Prof. Pfaundler has shown that an acid containing 66·19 per cent. of H_{2}SO_{4}, is the most advantageous to employ for this purpose; one part of an acid of this strength with 1·097 parts of snow forming a refrigerating mixture which will reduce the temperature to -37° C. (-36° F.). For practical purposes it is suggested an excess of snow would be better, since the refrigerating value of the mixture is thereby largely increased, though the lowest temperature is not obtained. See ICE.]

_Obs._ The materials in the first column are to be cooled, previously to mixing, to the temperature required in the second, by the use of other mixtures.

=REG′ULUS.= A term applied by the alchemists to various metallic matters obtained by fusion; as REGULUS OF ANTIMONY, ARSENIC, &c. It is now obsolete.

=REL′ISHES.= See SAUCES.

=REMEDIES, FERRUGINOUS.= Rob. Freygang:——

STEEL BRANDY is an ordinary clear brownish brandy, containing a very little bitter matter, like the stomachic bitters of the apothecaries, and mixed with about 1 per cent. of sugar. 10,000 parts contain about 1-1/2 part oxide of iron.

STEEL STOMACHIC BITTERS. This is more aromatic, but otherwise similar to the steel brandy; 10,000 parts contain 2/3 part iron oxide.

STEEL LIQUEUR is a clear, agreeably-tasting liqueur, of the colour and containing much of the juice of raspberries. 10,000 parts contain nearly 1,200 of sugar and only 1 of iron oxide.

STEEL SYRUP——Syrop ferrugineux de Quinquina. A clear slightly violet-coloured, thin, sweet fluid, containing spirit and sugar, of which cinchona bark may be an ingredient, though it is appreciable by neither taste nor tests. It contains 1-1/4 part iron in 10,000 parts.

STEEL BONBONS contain a trace of iron oxide.

The iron present in the above preparations is in the form of citrate. (Hager.)

=REMIT′TENT.= A term applied to fevers, and other diseases, which exhibit a decided remission in violence during the twenty-four hours, but without entirely leaving the patient, in which they differ from intermittents or agues.

=REN′NET.= _Syn._ RUNNET, PREPARED CALF’S MAW. The fourth or true digesting stomach of the calf, freed from the outer skin, fat, and useless membrane, washed, treated with either brine or dry salt for a few hours, and then hung up to dry. When well prepared, the dried ‘vells’ somewhat resemble parchment in appearance.

_Uses, &c._ Rennet is employed to curdle milk. A piece of the requisite size is cut off, and soaked for some hours in whey or water, after which the whole is added to the milk for curdling, slightly warmed, and the mixture is slowly heated, if necessary, to about 122° Fahr. In a short time after this temperature has been attained the milk separates into a solid white coagulum (curd), and into a yellowish, translucent liquid (whey). Two square inches from the bottom of a good ‘vell’ are sufficient for a cheese of 60 lbs. It is the gastric juice of the stomach that operates these changes. The stomachs of all sucking quadrupeds possess the same properties. See CHEESE.

=Rennet, Liquid.= _Syn._ ESSENCE OF RENNET. _Prep._ From fresh rennet (cut small), 12 oz.; common salt, 3 oz.; knead them together, and leave the mixture at rest, in a cool place, for 5 or 6 weeks; then add of water 18 oz.; good rum or proof spirit, 2 oz.; lastly, digest for 24 hours, filter, and colour the liquid with a little burnt sugar.

=Rennet, Liquid.= _Syn._ ESSENCE OF RENNET. Fresh rennet, 12 oz.; salt, 2 oz.; proof spirit, 2 oz.; white wine, a quart; digest for 24 hours and strain. A quart of milk requires 2 or 3 teaspoonfuls. WISLIN directs 10 parts of a calf’s stomach; salt, 3 parts. The membrane of the stomach is to be cut with scissors and kneaded with the salt, and with the rennet found in the interior of that organ; the whole left in a cool place in an earthen pot till the cheesy odour is replaced by the proper odour of rennet, which will be in one or two months. Then add 16 parts of water and 1 of spirit. Filter and colour with burnt sugar.

The German Pharmacopœia gives the following formula for liquid rennet:——3 parts of the mucous membrane of fresh calf’s rennet, macerated for three days in 26 parts of white wine, 1 part of table salt being added.

_Obs._ 2 or 3 teaspoonfuls will curdle a quart of milk. Some persons use white wine instead of water, with simple digestion for a day or two.

=RES′IN.= _Syn._ RESINA, L. This name is applied to many vegetable principles composed of the elements carbon, hydrogen, and oxygen. The resins (RESINÆ) cannot be very accurately defined, but we may in a general way describe them as substances which are solid at ordinary temperatures, more or less transparent, inflammable, readily fusible, do not volatilise unchanged, become negatively electrified by rubbing; are insoluble in water, but soluble in alcohol; mostly inodorous, and readily incorporated with fatty bodies by fusion. Their sp. gr. varies from ·9 to 1·2. According to Liebig, they are oxidised essential oils. Common resin, rosin, or colophony, and the shellac of which sealing-wax is made, are familiar examples of these substances. (See _below_.)

=Resin, Black.= _Syn._ ROSIN‡, BLACK R.‡, COLOPHONY; RESINA NIGRA, COLOPHONIA, L. What remains of turpentine after the oil has been distilled. When this substance, whilst still fluid, is agitated with about 1-8th part of water, it forms the yellow resin of pharmacy. Used for violin bows, dark-coloured ointments, varnishes, &c.

=Resin, Yel′low.= _Syn._ YELLOW ROSIN‡, WHITE R.‡; RESINA FLAVA, RESINA (Ph. L.), La. Detergent. Used in ointments, plasters, &c. (See _above_.)

=RES′INOIDS.= _Syn._ RESINOUS EXTRACTS, CONCENTRATED E.; EXTRACTA RESINA, L. Under this head, the so-called ‘Eclectics,’ who form a numerous class among American physicians, place their most important ‘concentrated remedies.’ “Viewed as pharmaceutical preparations eligible for use in medicine, though not purified so as to rank as distinctive proximate principles, these are very appropriately named ‘resinous extracts,’ or ‘resins.’ The term ‘resinoid,’ so commonly used, is less appropriate to the class, implying, as it does, a resemblance to resins, while all of these are either resins, oleo-resins, or more or less mixed proximate principles possessing no real resemblance to the class of resins.” (Parrish.) Most of them are prepared from plants indigenous to North America, by precipitating a strong alcoholic tincture with water. They are all brought to the condition of powder, those which are naturally soft and oily being mixed with a sufficient quantity of sugar of milk, or other dry material. One of these eclectic remedies has been introduced into regular practice. See PODOPHYLLIN.

=RESIN, or ROSIN OIL.= This is a product of the dry distillation of resin. The apparatus used consists of an iron pot, a head piece, a condensing arrangement, and a receiver.

In distilling the resin, a bright oil first comes over with water. As soon as a cessation in the flow of the distillate occurs the receiver is changed, and the heat is further raised, when a red-coloured and heavy rosin oil comes over. The black residue remaining in the pot is used as pitch. The light oil, called ‘pinoline,’ is rectified, and the acetic acid water passing over with it is saturated with calcium hydrate, filtered and evaporated to dryness; and the calcium acetate obtained is employed in the manufacture of acetic acid. The rosin oil, obtained after the light oil has passed over, has a dark violet-blue colour, and is called ‘blue rosin oil.’ The red oil is boiled for a day with water, the evaporated water being returned to the vessel; next day the water is drawn off, and the remaining rosin oil is saponified with caustic soda lye of 36° Baumé, and the resulting solid mass is distilled so long as oil passes over.

The product obtained is ‘rectified rosin oil,’ which is allowed to stand in iron vessels, protected by a thin layer of gypsum, whereby after a few weeks a perfectly clear oil is obtained free from water. The oil of first quality is obtained by a repetition of the foregoing operation upon the once rectified oil. The residues of both operations are melted up with the pitch.[137]

[Footnote 137: Dingler’s ‘Polytech. Journ.,’ ccvi, 246 (‘Journ. Chem. Soc.,’ new series, vol. xi, 304).]

Rosin oil is employed in the manufacture of axle grease, the oil being previously converted into a soap by heating with slaked lime.

=RESOLV′ENTS.= _Syn._ DISCUTIENTS; RESOLVENTIA, L. Substances or agents which discuss or resolve inflammatory and other tumours. See DIGESTIVES.

=RESPIRA′TION.= The peculiar function by which the blood is submitted to the action of the air, for the purpose of removing carbonic acid, and restoring its vitality by the absorption of atmospheric oxygen.

The air expired from the lungs is found to have undergone a most remarkable change. It is now loaded with aqueous vapour, whilst a considerable portion of its oxygen has disappeared, and its place is supplied by about a like volume of carbonic acid. It is no longer capable of supporting animal life, and even a lighted taper plunged into it is immediately extinguished. In the mean time the ‘venous blood’ which entered the lungs from the right chambers of the heart has lost its dingy hue, and has acquired the rich florid colour which is characteristic of ‘arterial blood.’ In this state it is returned to the left chambers of the heart, and is propelled by that organ to every part of the body, from which it passes by the capillaries to the veins, and by these again to the heart and lungs, to undergo the same changes and circulation as before. The carbon and hydrogen of the blood, ultimately derived from the food, are, in this course, gradually converted into carbonic acid and water by a species of slow combustion; but how these changes are effected is not definitely ascertained.

The lungs, as is well known, receive the atmospheric air through the trachea or windpipe. At the root of the neck this divides into two branches, called bronchi, and each bronchus, upon entering its respective lung, divides into an infinity of small tubes. The latter terminate in small pouches, called the air-cells, and a number of these little air-cells communicate together at the extremity of each small tube. The number of air-cells in the two lungs has been estimated at 1,744,000,000, and the extent of the membrane which lines the cells and tubes together at 1500 square feet. (Dr Addison.) Under ordinary circumstances, from 22 to 43 cubic inches of air are thrown out at each expiration; but, by a forced effort, 50 or 60 inches are ordinarily expelled. The number of respirations per minute in health, when the individual is tranquil and undisturbed, is about 15. Exercise increases this number. See FOOD, NUTRITION, &c.

=Respiration, Artificial.= Various means have been adopted for this purpose, among which blowing air into the lungs is, perhaps, that generally adopted. A better, and, in general, a much more efficient method, is as follows:——Powerful but not violent pressure is made upon the sides of the chest and upon the abdomen at the same time, by which the cavity of the thorax is diminished, and the air contained in the lungs is expelled; the compression is then suddenly withdrawn, when the elasticity of the ribs causes them to resume their old expanded positions; the chest is again enlarged, a partial vacuum is formed, and air rushes into the lungs, to be again expelled by pressure upon the ribs and abdomen as before. By this means artificial respiration may be kept up for a great length of time, without the use of bellows, or any other apparatus. The chief principle of Dr Marshall Hall’s so-called ‘ready method’ is the postural performance of artificial respiration. The patient is first placed gently on the face, and then turned on the side; then on the face again, alternately; these measures being repeated deliberately, efficiently, and perseveringly, fifteen times in the minute. When the prone position is resumed, equable, but efficient, pressure is applied along the spine; this pressure is removed immediately before rotation on the side.

The ‘Silvester method,’ invented by Dr Henry Silvester, is now acknowledged to be far more effective than Dr Hall’s method, and is adopted by the Royal Humane Society for the restoration of the apparently drowned. It consists in laying the patient on the back, slightly raising the head and shoulders, drawing the tongue forwards, and keeping it so by passing an elastic band over it and under the chin. The arms are then grasped just above the elbows, and drawn gently upwards until they meet above the head (this is for the purpose of drawing air into the lungs), keeping the arms in that position for two seconds. The patient’s arms are then turned down, and pressed gently and firmly for two seconds against the sides of the chest (this is for the purpose of pressing the air out of the lungs). Artificial breathing is thus carried on. These efforts are repeated fifteen times in a minute, until a spontaneous effort to respire is perceived. During the employment of these means the nostrils are excited with snuff or smelling salts, or the throat is tickled with a feather. After natural breathing has been restored, warmth and circulation are induced by wrapping the body in hot blankets, applying bottles or bladders of hot water, heated bricks, &c., to the pit of the stomach, the armpits, between the thighs, and to the soles of the feet, and by rubbing the limbs upwards firmly and energetically.

In the ‘Landw. Versuchs Stat.’ (xviii, 81-169)[138] Rudolph Pott has recorded a series of interesting experiments instituted with the object of determining the comparative quantities of carbonic acid excreted by respiration and perspiration in different species of animals in equal intervals of time; together with some experiments on the excretion of carbonic acid by the same animals under different physiological conditions.

[Footnote 138: ‘Journ. Chem. Soc.,’ 1876, vol. i, p. 721.]

The author states that in his researches he used an air tight box, with glass sides, in which the animal is placed, and through which the air can be drawn at any rate required by means of an aspirator.

The air before entering the glass chamber passes over caustic potash and through baryta water; after leaving the chamber it passes through three flasks containing known quantities of baryta water.

In the first part of this paper the author estimates the amount of carbonic acid excreted by different animals during the space of six hours, and under otherwise similar circumstances. The following are the most important conclusions he arrives at:——

1. The greatest quantity of carbonic acid in proportion to their weight is given off by birds. Mammals are the next in order. Insects exhale less than either of these.

2. Worms, amphibia, fishes, and snails form another group which excrete much less carbonic acid. Of these worms exhale the most and snails the least.

3. Those animals of the second group, which live in water, give off the greatest part of their carbonic acid to the air, and only a much smaller portion to the surrounding water.

4. Young animals excrete more carbonic acid than old ones; this is most marked in amphibia. For example 100 grams of an old frog (_Rana temporaria_) exhaled in six hours ·213 grm., whereas 100 grams of a young frog gave off in the same time ·765 grm.

5. The larvæ of insects exhale less carbonic acid than the insects themselves.

6. Different individuals of the same species exhale in the same time nearly the same quantity of carbonic acid in proportion to their body-weight.

In the second part of this paper the author describes experiments in the influence of coloured light on the excretion of carbonic acid; in the same animal (mouse) and for the same time.

He concludes that——

1. The excretion of carbonic acid is less in ordinary daylight than in coloured light.

2. The violet and red rays exercise the least influence on the excretion of carbonic acid, the green and yellow are the most active; and the milk-white and blue rays occupy an intermediate position. The relation of these different actions may be expressed by the following figures:——

Violet. Red. Milk-white.
86·89 93·38 100

Blue. Green. Yellow.
122·63 128·52 174·79

Finally, the author experimented with a mouse during the night, and found then the excretion of carbonic acid at that time is considerably less than during the day.

=REVALEN′TA ARABICA.= A mixture of the red Arabian or Egyptian lentil with barley flour, and a little sugar or salt. (‘Lancet.’) See LENTIL and REVALENTA.

=REVERB′ERATORY FURNACE.= See FURNACE.

=REVI′′VER.= _Prep._ 1. (BLACK REVIVER, PARIS’S ANTICARDIUM.)——_a._ Blue galls (bruised), 4 oz.; logwood and sumach, of each 1 oz.; vinegar, 1 quart; macerate in a closed vessel, at a gentle heat, for 24 hours, then strain off the clear, add iron filings and green copperas, of each 1 oz., shake it occasionally for a week, and preserve it in a corked bottle.

_b._ Galls, 1 lb.; logwood, 2 lb.; boil for 2 hours in water, 5 quarts, until reduced to a gallon, then strain, and add of green copperas 1/2 lb. Used to restore the colour of faded black cloth.

2. (BLUE REVIVER.) From soluble Prussian blue, 1 oz.; dissolved in distilled water, 1 quart. Used for either black or blue cloth.

=RHAM′NIN.= _Prep._ Express the juice from buckthorn berries scarcely ripe, which is to be rejected; boil the cake or residue with water, strain with pressure, and filter the liquid whilst hot; crude rhamnin will be deposited as the liquid cools, which, by solution in boiling alcohol and filtration, may be procured in crystals.

_Obs._ Buckthorn juice (succus rhamni), “the juice of the fruit of _Rhamnus catharticus_ (Linn.),” is officinal in the Ph. L.

=RHAT′ANY.= _Syn._ RHATANY ROOT; KRAMERIÆ RADIX (B. P.); KRAMERIA (Ph. L. E. & D.), RHATANIÆ RADIX, L. “The root of _Krameria triandria_.” (Ph. L.) It is stomachic, and powerfully astringent and styptic.——_Dose_, 20 to 60 gr., either in powder or made into a decoction or infusion. It is much employed in tooth powders, to fix the teeth when they become loosened by the recession of the gums, and also for improving the natural red colour of the lips and gums. A saturated tincture or fluid extract, made with brandy, forms the ‘wine-colouring’ used by the Portuguese to give roughness, colour, and tone to their port wine. Hard extract of rhatany is also much employed for the same purpose.

=RHE′IN.= _Syn._ CHRYSOPHANIC ACID. The yellow colouring principle of rhubarb.

=RHEUMATIC and GOUT PILLS.= (W. Gross Cardiff). Pills weighing 2 grammes rolled in lycopodium, the essential ingredients of which are quinine sulphate, gamboge, jalap, resin, and a little rhubarb. (Hager.)

=RHEU′MATISM.= _Syn._ RHEUMATISMUS, L. An affection of the joints, and of the external muscular, tendinous, and fibrous textures of the body, attended with swelling, stiffness, and great pain. Acute rheumatism or rheumatic fever,——arthritis, inflammation of the synovial membrane, or rheumatic gout,——sciatica, or rheumatism of the cellular envelope of the great sciatic nerve, affecting the hip,——and lumbago, or rheumatism of the loins, are varieties of this disease.

The treatment of rheumatism consists in the administration of purgatives and diaphoretics or sudorifics, accompanied by tonics, as bark, quinine, &c. Calomel with opium, and iodide of potassium, have also been frequently and successfully employed in this complaint. Of late years the administration of the bicarbonate, citrate, or nitrate of potassa, in rather large doses, has been strongly recommended, and in numerous cases adopted with success. Lemon juice, liberally taken, has also proved useful in suddenly cutting short severe attacks of certain forms of rheumatism. The compound powder of ipecacuanha, taken at night, will generally promote the ease and sleep of the patient, and, by its sudorific action, tend considerably to hasten a cure. Where possible, a dry atmosphere and a regular temperature should be sought, since a damp atmosphere, and, indeed, exposure to damp under any form, are the principal causes of rheumatism. Stimulating embrocations, blisters, frictions, and, above all, the hot or vapour bath, are also frequently serviceable in rheumatism, especially in lumbago and casual attacks arising from cold. The daily use of oranges, or of lemon juice diluted with water, has been found, in the majority of cases, to lessen the susceptibility of those who employ them to attacks of rheumatism and rheumatic gout arising from a damp situation or exposure to the weather. See LEMON JUICE.

=RHO′DIUM.= A whitish metal discovered by Wollaston, in 1803, associated with palladium in the ore of platinum.

It is chiefly employed for tipping the nibs of metallic pens (‘rhodium’ or ‘everlasting pens’). A very small quantity added to steel is said to improve its closeness, hardness, and toughness, and to render it less easily corrodible by damp.

=RHU′BARB.= _Syn._ RHEI RADIX (B. P.); RHEUM (Ph. E. & D.), RHEUM——Sinense (Ph. L.), RHABARBARUM†, RHŒM†, L. “The root of uncertain species of Rheum.” (Ph. L.) According to Dr F. Farre, the term ‘sinense’ (Chinese), employed by the London College, “was placed after ‘rheum,’ to include the so-called Russian and East Indian rhubarbs, which are considered to be the produce of China and Chinese Tartary, and to exclude European, Himalayan, &c.”

Three principal varieties of rhubarb are known in this country:——

Russian or Turkey rhubarb is the produce of six-year-old plants of the mountain declivities of Chinese Tartary; and its principal excellence depends on its more careful preparation, and subsequent garbling, both before its selection for the Russian market, and after its arrival at Kiachta, and again at St Petersburg. At Kiachta all pieces of a porous, grey, or pale colour are rejected, the whole being pared and perforated, the better to determine the quality of the interior portion. At St Petersburg the pieces are again carefully examined and garbled, and are, finally, packed in close cases or chests, which are rendered air-tight by the application of pitch on the outside.

East India or Chinese rhubarb is the produce of the locality just referred to, as well as of other parts of China. It is obtained from younger plants, and its preparation and subsequent selection or garbling is conducted with less care.

English rhubarb is principally produced at Banbury, Oxfordshire, from the _Rheum rhaponticum_. It is cut and dressed up after the manner of Turkey rhubarb, for which it is sold by itinerant vendors, habited as Turks.

_Adult._ Dr Maisch[139] says the presence of turmeric may be detected in powdered rhubarb by the following method:——A small quantity of the suspected rhubarb is agitated for a minute or two with strong alcohol, and then filtered, chrysophanic acid being sparingly soluble in this menstruum. The brown yellow colour of the filtrate is due to the resinous principles of rhubarb mainly; if adulterated with turmeric, the tincture will be of a brighter yellow shade; a strong solution of borax produces in both tinctures a deep red-brown colour.

[Footnote 139: ‘American Journal of Pharmacy,’ xliii, 259.]

If now pure hydrochloric acid be added in large excess, the tincture of pure rhubarb will instantly assume a light yellow colour, while the tincture of the adulterated powder will change merely to a lighter shade of brown-red.

The test is a very delicate one, and is based on the liberation of boracic acid, which imparts to curcumine a colour similar to that produced by alkalies, while all the principles of rhubarb soluble in strong alcohol yield pale yellow solutions in acid liquids.

_Qual._ Russian or Turkey rhubarb occurs in irregular plano-convex or roundish lumps, perforated with a circular hole; it possesses a yellow colour outside; when recently broken, the inside presents a rich mottled appearance, and evolves a peculiar and somewhat aromatic odour. It is firm, compact, heavy, perfectly free from moisture, and easily grated. Its taste is bitter, slightly astringent, and sub-acid; and when chewed it feels gritty, and tinges the saliva of a beautiful yellow colour. It breaks with a rough, hackly fracture, is easily pulverised, and its powder is of a bright buff-yellow colour.

East India, Canton, or Chinese rhubarb is in flat pieces, seldom perforated, and its taste and odour are stronger than the other. It is also heavier, tinges the saliva of an orange-red hue, and when pulverised the powder is redder than that of Russian rhubarb.

English rhubarb possesses all the preceding qualities in a greatly less degree. It is light and spongy, does not feel gritty between the teeth, its taste is mucilaginous, and its powder has a peculiar pinkish hue not present in either of the other varieties of rhubarb. As a medicine it possesses little value, and is chiefly employed to adulterate East India and Turkey rhubarb.

_Prop., &c._ Rhubarb is astringent, stomachic, and purgative. In small doses its operation is principally or wholly confined to the digestive organs; in larger ones, it first acts as a mild aperient, and, afterwards, as an astringent; hence its value in diarrhœa. It has also been used externally to promote the healing of indolent sores.——_Dose._ As a stomachic, 1 to 5 gr.; as a purgative, 10 to 20 gr. It is most effective when chewed, or in the form of powder produced by grating it.

=Rhubarb, Roast′ed.= _Syn._ BURNT RHUBARB; RHEUM USTUM, L. _Prep._ 1. Rhubarb, in coarse powder, is carefully and regularly heated in a smooth shallow iron disc, with constant stirring, until its colour has changed to a moderately dark brown, when it is allowed to cool out of contact with the air; when cold, it is reduced to powder, and at once put into a well-closed bottle.

2. (Hoblyn.) Roast powdered rhubarb, in an iron vessel, constantly stirring, until it becomes almost black; then smother it in a covered jar.——_Dose_, 5 to 10 gr.; as an astringent in diarrhœa, and a tonic in dyspepsia, &c. Prof. Procter, the well-known American Pharmaceutist, recommends the rhubarb to be only roasted to a ‘light brown.’

=RICE.= _Syn._ ORYZA, L. The seed of _Oryza sativa_, a plant of the natural order _Graminaceæ_. Several varieties are known in commerce, distinguished by the name of the country or district which produces them. The finest is that imported from Carolina. It reaches this country in a decorticated condition. ‘Paddy’ is rice with the husk upon it. Dr Letheby estimates that it affords nourishment to not less than a hundred millions of people.

As an article of diet, rice is highly nutritious and wholesome when combined with fresh animal or other nitrogenised food; but, owing to the very small quantity of ‘flesh-formers’ which it contains, and its comparative destitution in saline matter, it is totally unfit to form the principal portion of the diet of the working classes, or the poorly fed, at least in this climate. “It does not appear so well calculated for European constitutions as the potato, for we find the poor constantly reject it when potatoes can be had.” This preference evidently depends on something more than mere whim or taste, for some years ago, when rice was substituted for potatoes in some of our union workhouses, the most serious consequences followed. In one of these, nine or ten deaths from scurvy and allied diseases occurred in a single fortnight. Large quantities of rice are annually imported into Britain, and used by distillers in the manufacture of spirits.

Letheby gives the following as the composition of rice:——

Nitrogenous matter 6·3
Carbo-hydrates 79·5
Fatty matter 0·7
Saline matter 0·5
Water 13·0
——————
100·0

Payen gives the following as the composition of dried rice:——

Nitrogenous matter 7·55
Starch 88·65
Dextrin, &c. 1·00
Fatty matter 0·80
Cellulose 1·10
Mineral water 0·90
——————
100·00

Ash of rice:——

Potash 18·48
Soda 10·67
Lime 1·27
Magnesia 11·69
Oxide of iron 0·45
Phosphoric acid 53·36
Chlorine 0·27
Silica 3·35
——————
99·54

=Rice, To Cook.= If rice is boiled it should be subjected to a low temperature. The best way of cooking rice, however, is by thoroughly steaming it. By this method, it is said, the loss of nitrogenous matter is prevented, and the grain consequently suffers no diminution of nutritive power, as in the case of boiling.

_Microscopic appearance of Rice._

Fig. 1——Transverse section of the husk of rice.

Fig. 2.——Appearance of husk as seen in a transparent medium of glycerin and gum: _a_, Siliceous granules arranged in longitudinal and transverse ridges, perforated by openings——stomata, some having hairs over them. _b c_, Transverse and longitudinal, brittle, rough-edged fibres, _d_, A fine membrane of transverse angular cells; these overlie a very delicate membrane of large cells, _e_.

=RICINO′LEIC ACID.= A variety of oleic acid discovered in saponified castor oil.

=RICK′ETS.= _Syn._ RACHITIS, L. A disease, generally confined to childhood, characterised by a large head, prominent forehead, protruded breast bone, flattened ribs, tumid belly, emaciated limbs, and great general debility. The bones, more particularly those of the spine and legs, become distorted, and exhibit a deficiency of earthy matter; the stools are frequent and loose, a slow fever succeeds, with cough, painful and difficult respiration, and, unless the child rallies, atrophy is confirmed, and death ensues. When recovery takes place there is always more or less deformity left.

The common causes of rickets are bad nursing, exposure to damp and cold, and insufficient nutrition, arising from the use of white bread containing alum, or any of the pernicious compounds vended under the names of ‘FARINACEOUS FOOD,’ ‘INFANTS’ F.,’ ‘PATENT F.,’ &c. Rickets, like caries of the bones, is a disease which is scarcely known amongst infants whose pap is made of pure wheaten bread, and whose mothers or nurses consume the same themselves.

The treatment of rickets depends more on proper domestic management than on direct medication. Careful nursing, warm dry clothing, thorough ventilation, moderate exercise, and, above all, a light nutritious mixed diet abounding in nitrogenous matter and the phosphates, will do much to effect a cure. To these may be added the administration of the milder chalybeate tonics, bark, or quinine, with occasional doses of some mild aperient, as phosphate of soda, or, when there is diarrhœa, of rhubarb or some other tonic purge. The administration of small doses of phosphate of lime or of dilute phosphoric acid, frequently repeated, or, still better, the daily use of jelly made of pure ivory or bone shavings, will often effect wonders in those cases in which the bones are implicated from an apparent deficiency of earthy matter. See BREAD, FARINA, NURSING, &c.

=RING′WORM.= _Syn._ SCALD-HEAD; PORRIGO, L. The common ringworm, the PORRIGO SCUTULATA of medical writers, is a disease that appears in circular patches of little pustules, which afterwards form scabs, leaving a red pimply surface, and destroying the bulbs of the hair in its progress. It spreads rapidly, and is very infectious, often running through a whole school. It chiefly affects the neck, forehead, and scalp of weakly children, and frequently arises without any apparent cause, but, in general, may be traced to uncleanness, or contact with parties suffering from the disease.

The treatment of ringworm consists in shaving the part, and keeping it clean with soap and water, at the same time that an occasional mild saline aperient is administered, and a light, nutritious diet, of which the red meat and ripe fruits should form a portion, be rigorously adhered to. When the scabbing commences, dressings of tar ointment, or of the ointment of nitrate or red oxide of mercury, or a mixture of equal parts of the first and either the second or third, should be applied, in each case diluting the mixture with sufficient lard to adapt it to the state of irritability of the part. During this treatment the head should be covered with an ordinary nightcap, or some simple bandage, and not enveloped in a bladder or oil-skin case, as is commonly the practice, since the complete exclusion of atmospheric air tends to aggravate the disease.

=RI′′PENING.= See BREWING, MALT LIQUORS, WINE, &c.

=ROAST′ING.= Alexis Soyer recommends, “as an invariable rule,” that “all dark meats, such as beef and mutton, should be put down to a sharp fire for at least fifteen minutes, until the outside has acquired a coating of osmazome, or condensed gravy, and then removed back, and allowed to cook gently. Lamb, veal, and pork, if young and tender, should be done at a moderate fire. Veal should even be covered with paper.

“Very rich meat, if covered with paper, does not require basting. Fowls, &c., should be placed close to the fire, to set the skin, and in about ten minutes rubbed over with a small piece of butter, pressed in a spoon. Meats, whilst roasting, should be dredged with flour, just at the time when the gravy begins to appear; the flour absorbs it, and forms a coating which prevents any more coming out. Hares and small game should be treated in the same manner.”

Under ordinary circumstances as to the fire, and the distance between it and the joint, beef, mutton, and veal, take about 1/4 hour per lb. in roasting. Lamb, poultry, and small game, require only 12 to 14 minutes per lb.; whilst veal takes fully 15 minutes, and pork takes from 1/4 hour to 20 minutes, as they must always be well done. The flesh of old animals requires more cooking than the flesh of young ones; and inferior, tough, and bony parts than the prime joints and pieces.

Roasting is not an economical method of cooking pieces of meat abounding in bone or tendinous matter, since the nutritious portion of these is either destroyed or rendered insoluble by the heat employed. Thus, the raw bones from a joint are capable of affording a rich and excellent basin of soup, highly nutritious; whilst the bones from a corresponding joint which has been roasted are nearly worthless when so treated. The same applies with even greater force to the gristly and tendinous portions. A dry heat either destroys them or converts them into a horny substance, unfit for food; whilst by boiling they are transformed into a highly succulent and nutritious article of food, besides affording excellent soup or jelly. Hence the policy of ‘boning’ meat before roasting or baking it; or, at all events, of removing the bony portion which would be most exposed to the action of the fire. See BONE and JELLY.

=ROB.= _Syn._ ROOB. A term, derived from the Arabic, formerly applied to the inspissated juice of ripe fruit, mixed with honey or sugar to the consistence of a conserve of thin extract. Rob of elder-berries (ELDER ROB; ROOB SAMBUCI), juniper berries (JUNIPER ROB; ROOB JUNIPERI), mulberries (MULBERRY ROB; ROOB DIAMORUM), and walnuts (WALNUT ROB; ROOB DYACARYON), with a few others, are still found in some of the foreign Pharmacopœias.

=ROCK.= The popular name of a sweetmeat formed of sugar boiled to a candy, and then poured upon an oiled slab, and allowed to cool in the lump. It is variously flavoured.

=ROCK CRYS′TAL.= Native crystallised silica. See QUARTZ.

=ROCK OIL.= See PETROLEUM.

=ROCK SOAP.= A native silicate of alumina; used for crayons, and for washing cloth.

=ROC′KETS.= (In pyrotechny.) _Prep._ The CASES.——These are made of stout cartridge paper, rolled on a mould and pasted, and then throttled a little below the mouth, like the neck of a phial. The diameter should be exactly equal to that of a leaden ball of the same weight, and the length should be equal to 3-1/2 times the external diameter. Above the spindle there must be one interior diameter of composition driven solid. They are filled with the following mixtures, tightly driven in, and when intended for flight (SKY-ROCKETS), they are ‘garnished,’ and affixed to willow rods to direct their course.

The COMPOSITION.——1. (Marsh.)——_a._ For 2-oz. rockets. From nitre, 54-1/2 parts; sulphur, 18 parts; charcoal, 27-1/4 parts; all in fine powder, and passed through lawn.

_b._ For 4-oz. do. From nitre, 64 parts; sulphur, 16 parts; charcoal, 20 parts; as the last.

_c._ For 1/2-lb. to 1-lb. do. From nitre, 62-3/4 parts; sulphur, 15-3/4 parts; charcoal, 21-1/2 parts.

2. (Ruggieri.)——_a._ For rockets of 3/4-inch diameter. From nitre, 16 parts; charcoal, 7 parts; sulphur, 4 parts.

_b._ For 3/4- to 1-1/2-inch rockets, use 1 part more of nitre.

_c._ For 1-3/4-inch rockets, use 2 parts more of nitre.

_d._ By using 1 part less of charcoal and adding respectively 3, 4, and 5 parts of fine steel filings, the above are converted into ‘BRILLIANT FIRES,’

_e._ By the substitution of coarse cast-iron borings for filings, and a further omission of 2 parts of charcoal from each, the latter are converted into ‘CHINESE FIRE,’

HAND-ROCKETS and GROUND-ROCKETS are usually loaded with nothing but very fine meal gunpowder and iron or zinc filings or borings.

After SKY-ROCKETS and WATER-ROCKETS are charged, a piece of clay is driven in, through which a hole is pierced, and the ‘head’ or ‘garniture’ filled with stars, and a little corn-powder is then applied. See FIRES, STARS, and PYROTECHNY.

=ROLLS.= A variety of fancy bread, generally in the form of small semi-cylindrical cakes, prepared by the bakers, and intended to be eaten hot for breakfast. They differ from ordinary fine or French bread, as it is called, chiefly in containing more water. Some are wetted up with milk and water, and are hence called ‘milk rolls.’