.-, 



M is i iiv 



JMAXUASKSK, COBAIT, ETC. 



of antimony with hydrogen, M distinguishing it from 

 that uf wnmuo with the same gM.* 



M \N<; VNESK. 



TUM meUl i never found in a native state ; and it* 

 attraction for oxygon u *o great, that it almost imme- 

 diately in MPI into state of oxide after iu prepamion. 



y Do obUimxi fn>ni iu protoxide by fusing, - 

 pacing the Utu-r, with charcoal and borax, to an intense 

 white heat -Metallic ..i.g-~, 10 produced, present* a 

 umiUr appearance to ca*t-in>ii. which it resembles in 

 many other rospeota. Ita symbol is Mn ; the equivalent, 

 .. ; and iU specific gravity about 8. 

 As we have already stated, manganese readily unites 

 with oxygen. The iiivtoxido is to be obtained by passing 

 hydrogen gM over the binoxide ; and it forms salts with 



' acids, of which the sulphate is bext known. The most 



important oxide is that represented by the symbol 



i is largely employed in various ways. In 



I the laboratory it U used as a source of oxygen gas ; and 

 duced, by its aid, from common salt. In 



! Glasgow, Manchester, and Newcastle, immense quan- 



of the peroxide are employed in the manufacture 



Moride of limu ; and it is also used In orfoo-printuig, 



fur tin- purpose of producing brown and black colours. 



! Some of the salts of manganese have had similar appli- 



i cations to useful purposes ; and common writing-inks 

 have been made from them the advantage in their use 

 consisting in the fact, tli.it the marks produced cannot 

 be altered, but are rather deepened by age. Souieproto- 

 salts of manganese have been used as a test for the pre- 

 sence of ozone. For this purpose, manganic acid, Mn O 3 , 

 in combination with potash, as the manganate of potash, 

 ha* been proposed, which darkens to a purple tint as 

 the permanganate, on exposure to air containing free 

 ozone. The chief uses of the oxide of the metal, beyond 

 those already indicated, are in connection with the 

 manufacture of glass. If heated with oxide of iron 

 during the melting of glass, it deoxidises that metal, and 

 so diminishes the tint which oxide of iron affords. If 

 heated in quantities, it affords a blue or amethyst tint ; 

 and for a similar ol.j. ,; it has been employed in the pro- 

 duction of artificial gems. The chief source of proto-salts 

 is the carbonate, and in the manufacture of chloride of 

 lime: this is produced by converting the sulphate into 

 that salt, and thence obtaining the metal again in a state 

 of peroxide. We have observed this process adopted only 

 at the works of Messrs. Tennaut, of Glasgow. 



COBALT. 



TniR metal is, except in its state of combination, little 

 more than a chemical curiosity. It may be obtained 

 by heating the oxalate with charcoal : when fused, 

 it resembles a mass of cast-iron in many respects ; and, 

 amongst others, in that of being magnetic. Its equi- 

 valent is 29-5. Specific gravity a little over 8; and its 

 symbol, Co. 



In union with one equivalent of oxygen, it affords a 

 protoxide, which maybe obtained by adding a solution 

 of potash to the mil; lie, by which a hydrate is afford. <! 

 of a fine blue colour. If chlorine be transmitted 

 through water h"ld:i . the protoxide in suspension, the 

 esqui-oxide (Cot, Oi) is afforded. 



liloride of cobalt has been employed as a 

 yjn k. Words written by means of a cjiiil] 



pen with this ink are almost invisible, or of a very s 

 pink colour, if the solution be dilute. If. however, the 

 paper on which tln-y are written be held near tin 

 the writing will appear of a fine blue colour, which will 

 vanish on the paper becoming cool Landscapes pai 

 with this and the chloride of copper, have a very pretty 

 and interesting effect. 



to of cobalt is chiefly used as a blow-pipe test, 

 in which respect wo shall have to speak hereafter of it. 



The most important combination of cobalt, in a com- 

 mercial point of view, U that with siliceous matter, 



Hn mnlt, p. 111. 



which produces the substance called "smalts." This is 



.. 1 by roasting the ore, and subsequent f 

 with Ntud and potash, by nu-aim of which a kind of 

 glass is formed. This, iu the state of fine powder, 

 is employed by paper manufacturers, bleachers, and 

 others, for tin- purpose of giving a blue tint to their 

 goods. Uxido of cobalt is also employed in thu manu- 

 facture of artificial gems, to which it imparts a blue 

 colour. 



OHBOMIU1C 



IN its metallic state chromium is of no importance; 

 but in combination with potash as a chromafc, it is 

 largely used for various purposes. The metal is obtained 

 from its oxide by heating it with charcoal j owner and 

 oil, with which it is made into a paste. An intense heat 

 reduces the metal, which then presents several of tin 



rs of cast-iron. Its ore is a eliminate ot 'iron, found 

 in many parts of Europe. Chromium has an equiva- 

 lent of 267. Its specific gravity is nearly ; and its 

 symbol, < 'r. 



Chromium readily unites with oxygen, producing oxide 

 and an acid. The protoxide is an unstable compound, 

 passing rapidly to a greater state of oxidation. Tin 

 qui-oxide has a green colour, and may l>e produced by 

 heating eliminate of potash, and passing over it a stream 

 of chlorine gas, by which chloride of potassium and the 

 ii-oxide are afforded. This substance, in union with 

 iron, forms tho chromate of that metal, ami 001 

 the ore called chrome iron. 



Chromic acid is the most important of the ox\ 

 combinations. It results from a union t' m equivalent 

 of the metal with throe of oxygen, Cr Oj ; and may be 

 obtained from tho bichromate of potash by means of 

 sulphuric acid. The latter unites with the potash, 

 setting the acid free, which has, like some of its salts, a 

 rich ruby-red colour. Combined with potash it forms 

 both the chromate and bichromate the former affording 

 lemon-coloured crystals, and the latter having a 

 orange or red colour. The bieli u is used 



by calico-printers and dyers ; and chromate of 

 affords the well-known pigme - chrome yellow. A 

 higher state of oxidation affords porchromie '.old, which, 

 however, has not been completely investigated. 



Chromium combines with chlorine, formivv; two chlo- 

 rides. With oxygen and chlorine, chloro-cluomic acid is 

 produced. This may be obtained by fusing together 

 common salt and bichromate of potash ; and. by no 

 queutly adding sulphuric acid, and distilling the mixture 

 in a retort, the chloro-chroinic acid passes over as a 

 red-coloured liquid. The Other compounds of chromium 

 are of no special importance. The oxides are used 

 to produce coloured glass ; a-:i by the union with 

 potash and other alkalies, a kind of alum , prodi. 

 analogous to those afforded by alumin.i and tne alkalies. 



CADMIUM. 



OUR readers will have noticed that we have described 

 each metal in the order of its comparative value and 

 general importance ; and this < been chosen in 



the belief, that the general reader and the student would 

 have their interest in our subject best maintained. \\ V 

 are now approaching that limit beyond which the natural 

 history of the elements becomes a matter of importance 

 to the i 1 chemist only. 



Cadmium gem-rally occurs in combination with 

 and, like that metal, is volatile. It is dissociated from 

 zinc through its greater volatility ; and its pic 

 during the distillation of that metal, is evidenced i 

 production of a brown-colon red flame ; that of zinc having 

 a blue tint. Cadmium is somewhat like silver in appear- 

 ance, but much softer, and is readily fusible, 

 valent is .'ii; : specific gravity, 8'C j and its symbol U 

 Cd. Its combination! with oxygen and the salts pro- 

 duced from its protoxide, have no special application in 

 the arts, A'c., and are only of interest as the productions 

 of an individual element. 



