493 



CADET, LIQUOR OF. 



CADMIUM. 



494 



G therefore is no longer the dominant, but becomes the tonic ; con- 

 sequently a composition thus ending terminates irregularly, and not 

 with an imperfect cadence, if the accepted definition of the latter be 

 correct. 



Besides the perfect and imperfect cadences, many writers speak of 

 the interrupted or deceptive cadence. It is formed by a chord quite 

 foreign to that which was expected, thus evading the close, and 

 deceiving expectation. 



EXAMPLE. 



There is also another kind of cadence, to which the name oiplagal 

 is given ; and this is sometimes classed as an imperfect cadence. It 

 consists of the chord of the subdominant, followed by that of the 

 tonic, and is occasionally used in church and other sacred music. 



Sometimes in this cadence the chord of the subdominant is suspended 

 on part of the dual tonio. 



EXAMPLE. 



The term eadenee is also used to signify the addition made by the 

 performer at the close of an air or concerto, and supposed to be an 

 extemporaneous effusion, for the purpose of displaying such taste, 

 skill, and power as the composition itself affords no means of exhibiting. 

 The cadenza, however, if introduced at all, should always be in good 

 keeping with the air, &c., to which it is appended ; it ought to pre- 

 serve the game general character, and should invariably be brief, in the 

 instance of vocal music especially. Formerly the cadenza was, by 

 Italian as well as English singers, considered indispensable, and many 

 were the incongruous flights of ill-regulated fancy that audiences had 

 to endure. The French never admitted it ; the Italians have now 

 wisely discarded it ; and the Englinh have also begun to abandon it. 



The cadenza is go called, says Rousseau, because introduced gene- 

 rally on the first note of the final cadence. 



CADET, LIQUOR OF. [CACODYL.] 



CADI, according to Mr. Lane (' Arabian Nights,' vol. i.), Kddee, is a 

 judge or minister of justice, who passes sentence in all cases of law : 

 religious, moral, civil, and criminal. This he generally does, in the 

 present day, in accordance with the decision of a Mufti, or doctor of 

 the law. In small towns and villages he is often employed to draw 

 up written contracts of various kinds. The Persian pronunciation of 

 the word is Cdzi, sometimes written Jfazee or Kauzee. In the Moham- 

 medan states in India the cadi continues to be the chief judge ; but in 

 Turkey he is subject to the Mufti, and in Persia he stands under the 

 Sheikh-ul- Islam or supreme judge (literally "the elder or chief of the 

 faith "), in all the principal cities where an officer of that rank resides ; 

 and the latter functionary has in general the further gratuitous aid of 

 the council of Mullas (Moollahs) or learned men. 



The law of all Mohammedan nations, which is administered by the 

 cadis, is founded partly- on the Koran, and partly on the Sunnah or 

 tradition ; but in Persia, since the establishment of the faith of the 

 Shiitea as the national religion of the country, jurists have rejected all 

 traditions coming from the three first caliphs, Abu Bekr, Omar, and 

 Osman, or from other persons who opposed the right of Ali to the 

 succession of Mohammed. 



CAT)MIUM (C'd), Klaprothium, Mdin um, a peculiar metal, discovered 

 in 1818 ; it was found in some ores of zinc,and especially in the Silesian. 

 On account of the effect which was produced by the action of sulphu- 

 retted hydrogen upon some preparations of zinc, the presence of arsenic 

 was suspected, but the appearance was found to be owing to this new 

 metal. The first notice of its existence was by Hermann, but Stromeyer 

 more particularly examined and detailed it properties, and gave it the 

 name "ilamtne, or xaXfum, a name by 



which the common ore of zinc was formerly known. 



In order to separate cadmium from the mineral containing it, it is 



to be dissolved in sulphuric acid, and the solution, which should have 

 excess of acid, is to be diluted with water, and to have a current of 

 sulphuretted hydrogen gas passed into it, until a yellow precipitate 

 ceases to be formed. This precipitate is sulphuret of cadmium, which 

 is to be dissolved in concentrated hydrochloric acid, and the excess of 

 acid being expelled by evaporation, the residual salt is to be dissolved 

 in water, and precipitated by carbonate of ammonia, an excess of which 

 dissolves any oxide of zinc or copper that may have been thrown down 

 by the sulphuretted hydrogen with the sulphuret of cadmium. The 

 carbonate of cadmium thus obtained is to be heated to redness, to 

 expel carbonic acid, then mixed with lamp black, and heated to dull 

 redness in a glass or porcelain retort : it is thus reduced, and the metal 

 distilled. The impure Silesian oxide of zinc is stated to contain from 

 14 to 11 per cent, of this metal. 



Cadmium has the colour of tin, is brilliant, and susceptible of a fine 

 polish. Its fracture is fibrous, and it crystallises readily in regular 

 octahedrons ; while solidifying, its surface is covered with arborations 

 like fern leaves. It is soft, easily bent, filed, and cut ; it stains sub- 

 stances upon which it is rubbed, like lead. When bent it gives a 

 peculiar crackling noise, like tin. It is very ductile, easily drawn into 

 wire and beaten into thin leaves. Its specific gravity after fusion is 

 8'604, but when beaten 8-694. Cadmium melts below a red heat ; and 

 at a temperature a little below that of boiling mercury, it boils and 

 distils in drops. The vapour of cadmium has no particular odour. 

 Like tin it is slowly acted upon by the air, but is eventually tarnished 

 by it. 



Oxygen and Cadmium readily unite to form an oxide. It may be 

 procured either by burning the metal, by decomposing a solution of 

 the metal with an alkali and washing and calcining the precipitate, or 

 by igniting the carbonate or nitrate. The colour of oxide of cadmium 

 depends upon its state of aggregation ; it is either deep reddish yellow, 

 bright brown, deep brown, or even black. It is neither fusible nor 

 volatile, even at a very high temperature. Oxide of cadmium is 

 insoluble in water, but is precipitated in the state of hydrate by solu- 

 tion of potash ; this hydrate is white, insoluble in the fixed alkalies, but 

 soluble in ammonia. Carbonate of ammonia, however, does not dissolve 

 it, and this difference between it and oxide of zinc serves as a process 

 for separating them. Oxide of cadmium is composed of 

 1 Equivalent of oxygen = 8 

 1 cadmium = 5674 



Equivalent of oxide 6474 



Suboxtde of Cadmium (Cd 2 0), containing two equivalents of metal to 

 one of oxygen, is obtained when oxalate of cadmium is heated in a 

 retort to the melting-point of lead. It is a green powder. 



Nitrogen and cadmium form, according to Mr. Grove, a spongy, dark, 

 lead-gray substance, Its specific gravity is 4'8. 



No compound of hydrogen and cadmium is known. 



Chlorine and Cadmium combine to form only one chloride ; this 

 compound may be obtained by dissolving either the metal or its oxide 

 in hydrochloric acid. The solution, by spontaneous evaporation, is 



gradually converted into a mass of short satiny crystals, composed of 



1 Equivalent of chlorine = 35'5 



1 cadmium = 5674 



2 water =18 



110-24 



These crystals are readily soluble in water, and effloresce in warm 

 dry air. The effloresced salt fuses below a red heat, and on cooling it 

 assumes the appearance of a transparent, lamellated, crystalline mass, 

 which has a faint, pearly, metallic lustre. By exposure to the air it 

 acquires water, and falls to powder. 



No compound of carbon and cadmium is known. 

 Sulphur and Cadmium unite to form only one sulphide, which 

 consists of 



1 Equivalent of sulphur = 16-00 

 1 cadmium = 56- 74 



Equivalent of sulphide 7274 



This metal does not readily unite with sulphur when they are heated 

 together. The compound is more easily formed when the oxide is 

 heated with it, but the best method is to precipitate a salt of cadmium 

 with sulphuretted hydrogen. In this state it forms a pigment known 

 UMtHMOriSiovA It has a yellow colour, inclining to orange. It was 

 this colour which first led to the suspicion that zinc contained arsenic. 

 When heated to redness it becomes brown, and afterwards carmine 

 red, but on cooling it resumes its original colour. It is not decom- 

 posed at a high temperature ; but a strong white heat melts it, and 

 causes it to crystallise on cooling in transparent plates of a fine yellow 

 colour. Concentrated hydrochloric acid decomposes it with the 

 evolution of sulphuretted hydrogen, and without any deposit of 

 sulphur. Nitric acid converts it into sulphate of cadmium. Sulphide 

 of cadmium is insoluble in sulphide of ammonium ; this serves to dis- 

 tinguish it from sulphide of arsenic, which is soluble in that reagent. 



Sulphide of cadmium is also found native in the form of Greenwiite. 



P/iophorui and Cadmium combine readily ; the resulting phosphide 



