117 



COORDINATE* 



COPING. 



frame and belli removed. A fourth nuohine performs the operations 

 of chimin* and ervuxing. The cask, or ratlier the lUve-work which U 

 to fonu it* principal put, is made to ruUto honi.uit.illy in * Uthe, 

 while cutting chisels or other tooli trim the eixU in the modes which 

 cooper* nil chiming nd creuxin*. to enable the lUvea to fit into the two 

 eocU of the eak. A fifth nwrhine cuU the ends or brads of the casks. 

 The piece* of wood to form the brads and bottom are placed together, 

 and brought under the actjnu of a circular taw, which gives the requi- 

 site circular form, and at the tame time give* the bevel for adjusting 

 the bead to the (tare* ; by a slight adjustment of the medium m. the 

 head may be made oval instead of round. With two of the shaping 

 machines, one man can shape the edge* of the staves for a hundred 

 hogsheads in a day. 



Many modes are adopted for cleansing casks which have become foul. 

 They are washed with dilute sulphuric acid, or with a solution of 

 chloride of lime ; or are exposed to the mingled fumes of sulphur and 

 saltpetre ; or an- whitewashed with fresh milk of lime ; or are charred 

 by a fire of shavings ; or are affected with a sort of charring action by 

 very strong sulphuric acid applied to the wood when perfectly dry ; or 

 are exposed to high-pressure steam ; or are filled with a mixture of 

 charcoal and water, frequently agitated ; or ore soaked with a lye of 

 pearlash, lime, or alum. After any nf these processes the casks require 

 to be well rinsed with cold clear water. 



COORDINATES mean lines, angles, tic. ranged in order. The 

 notion from which the word arose was this, that when the positions of 

 consecutive points on a curve are referred to given points or lines by 

 means of lines (as in ABSCISSA) or angles, those lines or angles present 

 a succession of arranged data, by which the several points of the curve 

 may be treated in order. It was Descartes who first used coordinates 

 in the second book of his geometry, and the words in which this now 

 all-pervading method of expression was announced are as follows : 

 " tligo rectam aliquam lineam, veluti A B, ut ad diversa ejus puncta 

 raferam omnia puncta hujus curvte lines; c E ; dcinde eligo cti.im 

 punctum oliquod in A B, veluti A, ad ordicndum ab eo calculum." We 

 do not find the word in Schooton, Beaune, or others of the immediate 

 school of Descartes. Do Witt calls the abscissa rrm patient, and the 

 ordinate rriu rjKdmi. Coordinates (so called) are used in the writings 

 of John Bernoulli, but in Newton the phrase for them is " linese 

 ordinatim applicatK : " in later times the use of the word hag become 

 universal Coordinates either determine the position of a point in 

 space, or in a plane which is understood to contain all the figure 

 under consideration, as in the first six books of Euclid. They deter- 

 mine position either by straight lines only, or by a straight line and 

 angles : in the latter case they ore called polar coordinates. 



1. Rectilinear coordinates in a plane. In the given plane draw two 

 straight lines meeting in a point o (called the on' in). From any 

 point P draw parallels to the two lines just named : the parts inter- 

 cepted between P and these lines (called am} are the coordinates of 

 the point. When the axes are at right angles, the coordinates are said 

 to be rtcta*fflar ; when at another angle, oblique. [ABSCISSA.] 



2 Rectilinear coordinates in space. Through any point o (the 

 origin) draw three planes which intersect in right angles (the axes). 

 Through any point P draw parallels to the axes : the parts intercepted 

 between p and the coordinate planes (three in number) are the coordi- 

 nates of P. 



8 Polar coordinates in a plane. Choose any point o in the piano, 

 and any right line o A passing through o. Then taking any point p, 

 the distance O P (called the radivt rector) and the angle P o A (which 

 has no distinct name, but might be called the rectorial angle) are the 

 polar coordinates of p. 



4. Polar coordinates in space. Choose a plane (M), a point o, and a 

 line o A, in the plane M. Take any point P above or below the plane, 

 and let fall p B, a perpendicular on (M) meeting (M) in B. Then the 

 radius vector o P, and the angles p o B and BOA nre the polar coordi- 

 nates of f. In astronomy, if o be the earth's centre, o A the lino 

 passing through the equinox, and (M) the plane of the ecliptic ; then 

 B o A is the longitude of p, and p o B its latitude But if (M) be the 

 plane of the equator, then B o A is the right ascension of P, and P o B 

 its declination. 



COPAIBA or COPAIVA, an oleo-resin or turpentine (incorrectly 

 termed a balsam, since it is destitute of benzoic or cinnamic acid), i 

 procured not merely from the Copaifera nfficinalit (Willd.), a native of 

 Venezuela, also naturalised in the Antilles, but from ten to twelve 

 species, chiefly natives of Brazil. It varies in appearance and qualities 

 according to the species from which it has been procured, and likewise 

 according to the age of the tree and the time of tho year. Incisions 

 are mode in the tree, from which flows a liquid differing little in con- 

 sistence from thick sap. It is collected in calabashes, after which the 

 incisions are closed with wax or clay. The incisions are repeated in 

 general three times caoh season. The fluid is brighter or darker in 

 colour, more or less rich in volatile oil, more acrid or more bitter, 

 according to circumstance*. It Is mostly of a light yellow < 

 cl ar and transparent, seldom turbid or cloudy; odour peculiar, 

 volatile ; taste oily, mild, slightly aromatic, at last acridly bitter. 

 Specific gravity 0'C6 to 997, according to iU age. Exposed to heat 

 in a platinum spoon, it i* entirely consumed with a white smoke. In 

 * state of purity, it consists of a volatile oil, in the proportion of 

 40 per cent., and CO per cent, of an acid crystallisable resin (copaivio 



acid), with a soft brown resin. The oil may be separated by distillation, 

 or by means of mixing equal parts of copaiba with alcohol of specific 

 gravity 837, shaking them diligently, then mixing 100 parts of the 

 copaiva which has been so treated with 87} parts of a ley of caustic 

 soda, to be agara well shaken ; after which 150 part* of water are to be 

 thoroughly agitated with it, and tho whole left to rest The specific 

 gravity of the oil thus obtained is O-'JOO. A slight difference exists 

 between the oil thus procured and that by distillation. Both are used 

 in medicine; indeed thu oil is the active principle of copaiva, the 

 resin being of very secondary importance. The oil is destitute of 

 oxygen, and may be employed for the preservation of potassium. 



Copaiva is frequently adulterated : the presence of any extraneous 

 matters may be known by the manner in which the suspected portion 

 conducts itself towards solvents and re-agents. Copaiva is occasionally 

 mixed with castor-oil, almond, poppy, nut-oil, and the finer sorts of 

 turpentines. All fixed oils (except castor-oil, the presence of which 

 may be detected by sulphuric acid, but the accuracy of this test U 

 called in question by Brandes) separate from it by being allowed to 

 remain at rest. Good copaiva should be perfectly soluble in alcohul of 

 90 per cent It is soluble in all known ethers, and in the volatile and 

 fixed oils. Three parts of copaiva with one of caustic ammonia of 

 specific gravity 0'950 form by agitation a clear soap. The simplest 

 test of the purity of copaiva is to heat a small quantity in a watch- 

 glass, when, if good, a hard brittle resin remains, which has con- 

 siderable analogy with styracin. The crystals which form in this resin 

 are six-sided prisms, and have the property of polarising light 



A kind of copaiva is obtained in St. Domingo from the Cruton 

 oriijanifulitu (Lamarck); in Java and elsewhere the juice of the 

 Canorium commune (Linn.) is found to possess similar properties. A 

 wood oil from various species of Dipterocarput, especially D. lurbinalui, 

 is obtained in Moulmein, in the East Indies, and imported into 

 England (Royle). 



Copaiva acts as a stimulant to the mucous surfaces, especially of the 

 rectum and urino-genital passages : when the dose U small, it influences 

 the kidney and urethra ; but if large, the rectum. It is chiefly used 

 to lessen increased discharges from those organs, and if judiciously 

 employed, generally effects this object ; but if given prematurely or in 

 too large a dose, it seldom fails to aggravate the complaints and 

 occasion other serious symptoms. It has likewise been beneficially 

 given in affections of the mucous membrane of the lungs, such as 

 chronic bronchitis, which must be carefully distinguished from true 

 phthisis pulmonalis or consumption, a disease in which it cannot fail 

 to prove injurious. It sometimes occasions a singular eruption, 

 something like measles, and also a swelling of the joints resembling 

 rheumatism. 



Various means have been devised to conceal the disagreeable nauseous 

 taste of cojiaiva without impairing its qualities. Calcined magnesia, 

 thickens it, and permits it being made into pills ; an etherial or alkaline 

 solution will also retain the virtues, and lessen the repulsive taste. 



COPAIVIC ACID. [BALSAMS.] 



COPAL, a resin possessed of peculiar properties, the produce of the 



iui copalliitum, a native of Mexico ; it is in rounded masses, smooth 

 and brittle, transparent or nearly so, without colour, or baring a slight 

 tinge of yellow : it has but little taste, and is nearly inodorous ; it is 

 insoluble in water, fusible, and inflammable. It differs from most 

 other resins in its very sparing solubility in alcohol ; and of the little 

 that dissolves with the assistance of heat the greater part is deposited 

 as the solution cools. It is dissolved by ether and some essential oils. 



COPAL VARNISH is the substance for which gum copal is 

 chiefly employed. It is probable that every manufacturer has hi* 

 peculiar mode of proceeding : Tingry prepares the simple copal varnish 

 by heating eight ounces of oil of turpentine in a matrass with the heat 

 of a salt-water bath ; as soon as this reaches its boiling point, be 

 gradually throws in an ounce and a half of copal reduced to powder, 

 keeping the vessel in a state of circular motion. This author further 

 states that to obtain this varnish colourless, the rectified oil is to bo 

 exposed previously to the sun for sumo months in bottles, leaving an 

 interval of some inches between the cork and the surface of the liquid; 

 by this the oil undergoes some change, which renders it a better 

 solvent of copal. 



The varnish thus prepared is stated to be exceedingly durable and 

 brilliant; it resists scratches, and is susceptible of a fine polish. 

 Tingry particularly recommends it to be applied to philosophical 

 instruments. There are several modifications of this varnish used for 

 particular purposes, as with the addition of oil of lavender and oil of 

 lavender and camphor, an account of which may be seen in the author 

 above named. 



The relation which copal bears to other varnishes will be pointed 

 out in a later article. [VARNISHES.] 



COPARCENERS. [PARCENERS] 



COPERNICAN SYSTEM. [CopEPKiccs in Bioo. Dnr.] 



COPINO, the stone, brick, or plaster cap or covering of a wall, "a 

 term perhaps derived from the Italian eoprire, to cover. Some think 

 it is derived from the German /"//. or Dutch kop, the bead. Coping- 

 stones are placed on the tops of walls to protect them from the weather. 

 Plat coping is called parallel cajrini;, and is used upon inclined surface*, 

 as on the gables and parapets of houses, and also on the tops of garden 

 and other walls. Ftather-tdged coping has one edge thinner than the 



