Cooley's Cyclopaedia of Practical Receipts Volume I Part 146

_The Remedy._--Sulphite of magnesia, 2 dr., sulphurous acid, 2 oz.; water, 2 oz.; tincture of capsic.u.m, 1/2 oz.; sulphate of morphia, 2 gr. Mix and dissolve; a teaspoonful every half hour until relieved.

=CHOLERA MEDICINE.= The expressed juice of dandelion and milfoil mixed with brandy spirit. (Dr Horn).

=CHOLES'TERIN.= C_{2}_{6}CH_{4}_{4}O.H_{2}O. This substance is found in the bile, brain, nerves, blood, &c., and forms the princ.i.p.al ingredient of biliary calculi (gall-stones).

_Note._--The remedies containing astringents are the most efficacious.

=CHOL'IC ACID.= _Syn._ GLYCO-CHOLAL'IC ACID. A peculiar acid, existing as cholate of sodium, and a.s.sociated with choleic acid in the bile. It is a conjugate compound of cholalic acid with a nitrogenised substance called glycocin.

=CHON'DRIN.= Gelatin obtained from cartilage. It differs from ordinary gelatin in being precipitable by acetic acid, alum, and acetate of lead.

=Ch.o.r.eA.= [_Syn._ _St. Vitus's Dance._] A spasmodic disease affecting children and young persons, especially girls, between eight and sixteen years of age. It is caused by a debilitated condition of the nervous system, as well as by brain disease, scrofula, imprudent diet and worms.

The treatment recommended is the regulation of the bowels by mild purgatives. If the disease can be traced to worms, these should be removed by the proper remedies. If worms are not the cause, recourse should be had to the cold, or shower-bath. The hot hip-bath will be found serviceable in some cases. Where there is paleness of the skin any of the iron preparations will prove of great use, the bowels being kept regular. The best preparations of iron are either the tincture of the perchloride, or nitrate, or the citrate of iron and quinine. Some pract.i.tioners recommend a.r.s.enic--five drops of the solution (for an adult) twice a day after meals; others valerianate of zinc.

_Treatment for the Horse and other Animals._--Similar to the above.

=CHRISTOFIA= is a stomachic brandy or wine made of 1500 parts white wine, 20 parts cinnamon, 10 parts cloves, 60 parts bitter almonds, digested several days; 300 parts of sugar and 500 of spirit are then added, and the whole filtered. (Hager).

=CHROMACOME.= For dyeing the hair black. This is said to be prepared from harmless vegetable materials, but really consists of pyrogallic acid and nitrate of silver.

=Chromacome.= This is a French preparation which "contains nothing injurious to health." This hair dye consists of two fluids. The first, "Le chromacome, teinture superieure de William W. A. T., No. 1, Bonn,"

weighing about 45 grammes, is tincture of galls. The other, No. 2, is a solution of acetate of iron with a little nitrate of silver. When grey hair is moistened first with No. 1, then with No. 2, it becomes blackish-brown or black.

=CHRO'MATE.= _Syn._ CHRO'MAS, L. A salt in which the hydrogen of (hypothetical) chromic acid, HCrO_{4}, is replaced by a metal or other basic radical.

=Chromates=:--

_Prep._ The insoluble chromates, as those of barium, zinc, lead, mercury, silver, &c., may be made by mixing a soluble salt of those bases with neutral chromate of pota.s.sium. The first three are yellow; the fourth brick-red; and the fifth reddish-brown, or ruby red when crystallised. The soluble chromates may all be made by direct solution of the base in the acid, or by double decomposition. The chromates of commerce are prepared from either chrome ore or chromate of pota.s.sium.

_Prop., Uses &c._ The chromates are characterised by their yellow or red colour, the latter predominating when the acid is in excess; and except those with the alkaline bases, they are, for the most part, insoluble in water. Both the chromate and the bichromate of pota.s.sium are extensively used in dyeing and calico-printing. The former is employed in conjunction with sulphuric acid in the laboratory as an oxidising agent and in the manufactory for bleaching sperm oil. The bichromate of ammonium and pota.s.sium are used in photography.

They are readily recognised by the following tests:--

On boiling a chromate in hydrochloric acid mixed with alcohol, chromic acid is first set free, and then decomposed, forming a green solution of chloride of chromium. Sulphuretted hydrogen and sulphurous acid effect similar changes. With acetate of lead the chromates give a yellow precipitate; with nitrate of silver, a reddish-brown; with nitrate of mercury, a red one.

=CHROME ALUM.= See ALUMS.

=CHROME GREEN.= See GREEN PIGMENTS.

=CHROME IRON.= See IRON.

=CHROME RED.= See RED PIGMENTS.

=CHROME YELLOW.= See LEAD, CHROMATE OF.

=CHROMIC ACID.= See CHROMIC ANHYDRIDE.

=CHRO'MIUM.= Cr. A metal discovered in native chromate of lead by Vauquelin in 1797. It is found in the state of oxide, combined with oxide of iron, in some abundance, in the Shetland Islands, and elsewhere; as chromate of lead it const.i.tutes a very beautiful material.

Prepared in an impure condition as a white, very infusible, hard metal, by igniting the oxide with charcoal, at a white heat, in a lime crucible.

=Chromous Chloride.= CrCl_{2}. _Syn._ PROTOCHLORIDE. _Prep._ Ignite the chromic chloride in a current of dry hydrogen. A white, foliated ma.s.s, soluble in water (evolving much heat), and yielding a blue solution, which absorbs atmospheric oxygen with astonishing rapidity, acquiring a deep-green colour, and pa.s.sing into the state of oxychloride of chromium.

It is the most powerful reducing or deoxidising agent known.

=Chromic Chloride.= Cr_{2}Cl_{6}. _Syn._ SESQUICHLORIDE. _Prep._ Pa.s.s dry chlorine over a mixture of sesquioxide of chromium and charcoal, heated to redness, in a porcelain tube. The chloride collects as a sublimate, of a peach or violet colour, in the cool part of the tube.

Dissolve chromic oxide in hydrochloric acid and evaporate to dryness; the residue is chromic chloride. It forms a dark green ma.s.s, containing water, which is evolved by igniting at a temperature of 400, turning a purplish red.

=Chromium Oxides=:--

=Chromous Oxide.= CrO. _Syn._ PROTOXIDE OF CHROMIUM. This oxide has not yet been obtained in a satisfactory manner, but the hydrate is prepared by the addition of pota.s.sium hydrate solution to a solution of chromous chloride or sulphate. A brownish-red powder, speedily pa.s.sing to a deep foxy-red, with disengagement of hydrogen, and forming pale blue-coloured salts with the acids, which absorb oxygen with avidity, whilst the metal pa.s.ses into a higher state of oxidation.

=Chromic Oxide.= CrO_{3}. _Syn._ SESQUIOXIDE. Prepared by igniting pota.s.sium bichromate at a red heat and well washing the residue, and as hydrate by cautiously adding equal parts of hydrochloric acid and alcohol or sugar to a boiling solution of chromate of pota.s.sa in water, in small portions at a time, until the red tint disappears, and the liquid a.s.sumes a green colour; pure ammonia, in excess, is next added, and the precipitate which subsides is collected and washed with water.

_Prop., &c._ The anhydrous oxide is a rich crystalline, green powder, insoluble in both water and acids; fused with borax and gla.s.s, it imparts a beautiful green colour.

The hydrate is soluble in the acids and in alkaline lyes; with the first it forms salts which have a green or purple colour. These compounds may be made by direct solution of the hydrate in the dilute acids. Chromic sulphate combines with the sulphates of pota.s.sium and ammonium, giving rise to salts (CHROME ALUMS) which crystallise in magnificent octahedrons of a deep claret colour. The finest crystals are obtained by spontaneous evaporation.

These salts of chromium are the most important, the chromous salts being seldom met with, and are best recognised by the following reactions:--Caustic alkalies precipitate the hydrate, easily soluble in excess of the precipitant. Ammonia the same, but the precipitate is nearly insoluble. The carbonates of pota.s.sium, sodium, and ammonium throw down a green precipitate of carbonate and hydrate, slightly soluble in a large excess. Sulphuretted hydrogen causes no change.--Sulphydrate of ammonium precipitates the hydrate of a bluish-green colour.

=Chromic Anhydride.= CrO_{3}. _Syn._ CHROMIC ACID, ANHYDROUS CHROMIC ACID, CHROMIC TRIOXIDE. _Prep._ By conducting gaseous fluoride of chromium into a silver or platinum vessel, the sides of which are just moistened with water, and the aperture covered with a piece of moist paper, the anhydride will be deposited under the form of red, acicular crystals, which will nearly fill the vessel. When the process is skilfully conducted, the product is of exquisite beauty and chemically pure. The fluoride referred to above is obtained from fluor spar, 3 parts; chromate of lead, 4 parts; fuming (or the strongest) sulphuric acid, 5 parts; mixed cautiously in a silver or leaden retort. A red-coloured gas is evolved, which acts rapidly on gla.s.s, forming fluosilicic acid gas, and upon water forming hydrofluoric acid and chromic anhydride. The moisture of the atmosphere is sufficient to effect the decomposition last referred to; the former substance escaping as gas, and the latter being deposited in small crystals.

It is also prepared nearly pure by adding a cold saturated solution of pota.s.sium bichromate to once and a half its bulk of pure strong sulphuric acid. As the liquor cools, the anhydrous chromic acid is deposited under the form of brilliant crimson-red prisms; the mother-liquor is then poured off, and the crystals, placed between two tiles of gla.s.s or porcelain, are submitted to strong pressure for some time, under a bell-gla.s.s or jar, when the anhydride will be found sufficiently dry. It may be deprived of a little adhering moisture by placing it over sulphuric acid for a short time _in vacuo_.

Commercially, it is prepared by one of the two following processes:--

To a saturated solution of chromate of pota.s.sium, 100 parts, add oil of vitriol (sp. gr. 1845), 49 parts; and let the whole cool. This is the common process. The product contains sulphate of pota.s.sium, but this does not much interfere with its value as a bleaching agent.

From chromate of barium, decomposed by concentrated nitric acid. The anhydrous chromic acid is separated from the nitrate of barium by decantation, or, which is still better, by filtration through gla.s.s or asbestos. It is then evaporated to dryness, when the nitric acid is volatilised, and pure chromic anhydride left behind. The volatilised nitric acid may be condensed, and again used for the same purpose. The only precautions necessary to ensure the purity of the anhydrous chromic acid prepared by this plan are--to use a sufficient quant.i.ty of nitric acid and to take care that the nitric acid is sufficiently concentrated and pure.

_Prop., &c._ Forms ruby-red anhydrous prisms, very soluble in water, with formation of true chromic acid, and extensively manufactured for the purpose of oxidising and bleaching substances.

=CHROME IRON-STONE.= _Syn._ CHROME IRON-ORE. FeO.Cr_{2}O_{3}. This, which is the princ.i.p.al ore of chromium, corresponds in composition to brown oxide of chromium and to the magnetic oxide of iron; part of the iron, however, is generally displaced by the isomorphous metal magnesium, and part of the chromium by aluminium.

Chrome iron-stone is often met with in the form of octohedral crystals.

Acids fail to dissolve it, and it cannot be fused in the furnace, but when heated it absorbs oxygen from the air. This oxidation may be effected very readily if the chrome ore reduced to very fine powder be mixed with a carbonate of one of the metals of the alkalies or alkaline earths, a chromate of the base being formed.

=CHRYSENE.= C_{18}H_{12}. A hydrocarbon found by Laurent in crude anthracene. It occurs in bright yellow, glistening scales. It may be obtained colourless by heating the yellow crystals with hydriodic acid and amorphous phosphorus to 240. It cannot be sublimed without decomposition.

Chrysene is very slightly soluble in cold alcohol, ether, benzene, and glacial acetic acid. In carbon disulphide it dissolves somewhat more readily. Its melting point is from 248 to 250, and it boils at a temperature beyond that which can be registered by the mercurial thermometer.

=CHRYSOPHANIC ACID.= See RHEIN.

=CHYLE.= _Syn._ LYMPH. This is the name given to the nutritious milky fluid generated during digestion, and absorbed from the intestines by a set of vessels called the _lacteals_, which carry it to the thoracic duct, whence it is immediately conveyed into the circulation.

=CHYME.= The pulpy ma.s.s formed by the food in its first great change, in the process of digestion.

=CIDER.= _Syn._ CYDER; POMACEUM, L. Cider is the fermented juice of the apple, and is a very ancient beverage. Pliny calls cider and perry the "wine of apples and pears."