4< 



( AKMH'M. 



ru.\. 



h my, has a weak metallic liutre. in brittle, and but nightly fusible. 

 When heated in open vessels it bums with a very lirij-bt phosphoric 

 flutir, and U c>m, rtod int<> phosphate of cadmium. It dissolve* in 

 hy.lnn-hl.Tie acid with the evolution ..f ph.wphuivttvd hydrogen gas. 



"/./if UNI' CIK/MINMI may be mado to combine by treating the 

 metal with iodine, either in the moist or dry way. Iodide of cadmium 

 furma large hexagonal tubular crytaki, whieh are colourless and trans- 

 parent, haTe a ahining |-.vly luitre, ami d.i not alter by ex->osure to 

 the air. This alt u readily aoluble both in water and in alcohol. 

 The crynUu- fuae readily, losing their water of crytalliaation, and 

 again rryttalliiing At a higher teni|>eratur this salt is decomposed, 

 iodine vapouriaing, and metallic cadmium being left. It is composed 

 of 



1 Equivalent of iodine = 126*80 

 1 cadmium = 5674 



Equivalent = 183'54 



Iodide of cadmium as an eitemal remedial agent is said to be 

 superior to all other iodides used for that purpose. It is not decom- 

 posed by air r light, and hence, preference ia given to it in the pre- 

 paration of iodised roll. x lion for photographic experiment*. 



BromiiK a*J I'wlmium combine at a red heat, funning bromi.lt> <>f 

 cadmium. It readily fuses, and at a high temperature sublimes in 

 white pearly lamina". It is soluble in water, and on evaporation in 

 obtained in white needles containing 



1 Equivalent of cadmium = 5674 

 1 bromine = 80-00 



1 water = 36'00 



Equivalent 17274 



Fln'irite and Cadmium form a fluoride which la but little soluble in 

 water, but more so when acid is in excess. On evaporating the 

 solution an irregular cruet is deposited, which adheres to the vessel. 

 It u composed of 



1 Equivalent of fluorine = 19-00 

 1 cadmium = 5674 



Equivalent = 7574 



The various oxy-acids combine with oxide of cadmium to form Baits, 

 the general properties of which are, that a considerable number of 

 them are soluble in water, and the solutions are in general nearly or 

 quite colourless : the insoluble salts are also commonly devoid of 

 colour. The soluble salts are decomposed by ammonia and the fixed 

 alkalies, they throwing down white hydrate of cadmium, whirh an 

 excess of ammonia re-dissolves. The alkaline carbonates precipitate 

 white carbonate of cadmium; sulphuretted hydrogen occa- 

 yellow deposit ; ferrocyanide of potassium, a white one ; and infusion 

 of galls produces no effect. A plate of zinc throws down metallic 

 cadmium. 



The cadmium salts have a disagreeable metallic taste, and ore 

 powerfully emetic. 



Xitratt of Catlmimn crystallises in radiating needlea, which attract 

 moisture from the air, and are very aoluble in water and alcohol. 

 This salt consists of 



1 Equivalent of nitric acid = 54-00 



1 oxide of cadmium = 6474 



4 water = 38-00 



Equivalent = 15174 



Carbonate of Cadmium is readily obtained by adding a solution of 

 carbonate of soda to one of nitrate of cadmium. It is a white insipid 

 powder which in insoluble in water. When heated it is decomposed, 

 owing to the expulsion of the carbonic acid. It is constituted of 



1 Equivalent of carbonic acid = 22-00 



1 oxide of cadmium = 6474 



Equivalent = 8074 



' ' 'ii'Imimn crystallises in large transparent prisms, much 

 resembling sulphate of zinc in appearance. This salt readily dissolves 

 in water. It effloresces when exposed to the air, and at a low heat 

 lose* iU water of crystallisation without fusing. The dry salt in not 

 easily decomposed, a low red heat not being sufficient to expel the 

 iilphuric avid : but at a higher t<'Hi|HTnture it loses part of its sul 

 pliuric acid, and become* a subsulphatc. Its constituents I 



1 Equivalent of sulphuric acid = 40-00 

 1 oxide of cadmium = 64-74 

 4 water = 36-00 



Equivalent = 140-74 

 A (dale of Cadmium crystallises in fine needles, which are readily 



soluble in water, and do not alter in the air; they are composed 

 of 



1 Equivalent of acetic acid = 51 no 

 .1 oxide of cadmium = < 



2 water = 18-00 



Equivalent = 13374 



These are the moat important crystallisable salts of cadmium ; with 

 phosphoric, boracic, oxalic, arsenic, tartaric, and citric acids, oxide of 

 cadmium forms salts which are nearly or quite insoluble in wut<-r. It 

 forms also double compounds with several salts of the alkalies. 



Alinyt of Cadmium. Several metals readily combine with cadmium, 

 and form with it brittle alloys, and when they are Btrongh 

 cadmium is volatilised. 



< ',./,/:< i- inn/ ('mluiium form a yellowish white brittle alloy, and a 

 small quantity of cadmium is sufficient to produce Hi!- . II. vt ; 100 

 parts of copper retain 82'2 of cadmium when exposed to a red heat, 

 luit wln-n the alloy is heated to the fusing point of copper, th 

 tnium U volatilised entirely. 



flatiuuni tni<l L'niliiiiuiii yield an alloy which is of a silver white 

 colour, brittle, and not readily fusible; 100 parts of platinum retain 

 ] 17'3 of cadmium at a red heat. 



/rirun/ ami Ciiilmium readily unite, and form a fine argentine 

 amalgam, which crystallines in octahedrons. The crystals fall t.. the 

 bottom of the mercury, and are consequently of greater specific gi 

 The saturated amalgam is composed of 78'26 of mercury, and 21*74 of 

 cadmium. 



( '.idmium not having been long discovered, no very great use baa 

 been made of it. If larger quantities of it should be obtained, its 

 malleability may render it useful for several purposes. Sulphate of 

 cadmium has been used in medicine as a substitute for that of zinc 

 in collyria, but whether with any advantage over it has not been 

 determined. 



CA'DMIUM, ORES OF. Properly speaking, no ore of this metal 

 lias yet been discovered, except, the sulphide mentioned ; for it occurs 

 in such small quantities in the other minerals in which it has been 

 detected, that it may rather be considered aa an accidental impurity 

 than an essential constituent part. It is thus usually found associated 

 with the ores of zinc, the greatest proportion t>eiug found by 

 Stromeyer to be about five per cent, in the radiated zinc-blendes of 

 Bohemia. It has also been found by Dr. Clarke in the oxides of zinc, 

 both of Freiburg and Derbyshire ; and ita presence may also be gene- 

 rally detected in the common zinc of commerce, and may usually be 

 obtained in considerable quantity mixed with the soot from th 

 crucibles in which the oxides of zinc are reduced by being heated with 

 coal. Portions of tliis substance from the zinc works of liri-itol were 

 found to contain from 12 to 20 per cent, of cadmium. 



CAUU'CEUS, a staff of laurel or olive, with a representation of two 

 Kiiakea twisted about it. The caduceus was a xymlKi] of Hermes or 

 Mercury, t" whom, according to the fable, it was given by Apollo, in 

 return for the lyre which Mercury hod presented to him. It \v 

 the bodge of the heralds of ancient Greece ; and the name, which in 

 also written Caduc.um. is apparently only a corruption of the Greek 



pvufior tkeiyki I.DI i. herald's staff. In its oldest form it was merely 

 a bough, like the Greek iKfrfytov (Uketvrion), and the Itoman *y . 

 twined aliout with white wool. Afterwards a white or gilded staff, 

 with imitations of foliage and ribands, was sulwtiluted for the old 

 rude symbol. These were pn.lul.ly not turned into snakes till a much 

 later age, when that reptile had acquired a mystic character. .M.my 

 explanations of the caduceus have been attempted by modern scholars ; 

 that of Bottiger is plausible, who supposes that it was a representation 

 of a peculiar knot (the ,,,.,1,13 llerculi*, Hacrob. I., Saturn, c. lit) used 

 by the Pbccnicians in cording up their packages, and thence adopted 

 by them as a means of signifying to the inhabitants of the countries 

 on which they landed, their wish to lie upon a friendly footing with 

 them ; and as the Phoenicians were, generally speaking, the first 

 strangers with whom any people of C recce had intercourse, their 

 symbol of amity would probably be used for the same purpose, whcn- 

 11 occasion offered. (Bottiuger, ' Vasengemolde,' part ii. p. !7 : 

 ' Amalthe.i.' vol. i. p. 110); but the most probable, as it is the most 

 simple, is that of Mullcr, who says that it was originally the olive- 

 branch with the <rriitfta.ru, which later became developed into serpents. 

 (' Archaologic der Kunst.' j :t7'.i.) 



c. Kl. I'M SCALPTO'UIS, the sculptor's tool, a constellation of 

 Lacaille. It is situated below Coluinba Noachi and Canis Major, 

 low enough not to rise in this country. The following are the prin- 

 cijal stars in this constellation : 



Character. 

 8 



a 

 I 

 7 



No. In Catalogue 

 of Fiuul. 

 129 

 17S 

 181 

 808 



No. in Catalogue. 



of llritUh 



Association. 



1413 



1458 



1464 



1573 



Magniluilr. 

 4 

 4 

 4 

 4 



C-.-ESU'RA, or its Greek equivalent TO-< (that ia, rutti*;/, the two 

 words being respectively derived from the stems eatd and tern, cut), is 



