48 



CHEMISTRY. 



lit proper- 

 tin. 



yttria, thin procured, is a fine white powder with- 

 out taste or smelL It has no action on vegetable 

 ^' blues. Heat does not melt it. Its specific gravity 



It is insoluble in water, but, like alumina, it retains 

 a portion of that liquid, though Dot with so much ob- 

 stinacy. 



It is insoluble in the liquid fixed alkalies ; but it 

 dissolves in carbonate of ammonia, and in all the other 

 alkaline carbonates. 



It does not combine with oxygen, the simple com- 

 bustibles, or azote. 



According toEkeberg, when yttria is treated with 

 muriatic acid, a quantity of chloric gas is formed. If 

 so, it must contain oxygen, and of course he a me- 

 tallic oxide. The opinion is probable, though no at- 

 tempts have been made to decompose yttria by means 

 of galvanism. 



SECT. III. Of Glucina. 



Glucina Glucina was discovered by Vauquelin in the two 



minerals called beryl and emerald. They are pound- 

 how ob- ed and fused with thrice their weight of potash. The 

 tained. mass is dissolved in muriatic acid, and the solution 

 evaporated to dryncss. The residuum is digested in 

 water, and thrown upon the filter. The liquid which 

 passes through is mixed with carbonate of potash, 

 and the precipitate dissolved in sulphuric acid. Sul- 

 phate of potash being added to the solution, it is laid 

 aside for some time. Alum crystals gradually form. 

 When no more appear, 61ter the liquid, add carbon- 

 ate of ammonia in excess, filter again and boil the 

 liquid for some time. A white powder precipitates, 

 which is glucina. 



lu proper- Glucina is a soft white powder, without either 

 tie*. taste or smell. It adheres strongly to the tongue, 



produces no change on vegetable blues, does not melt 

 when heated, and does not harden and contract like 

 alumina. Its specific gravity is 2.976. It is insolu- 

 ble in water, but forms with it a paste having some 

 ductility. 



It does not combine with oxygen, nor with the 

 simple combustibles, or azote. 



It is soluble in the liquid fixed alkalies, like alu- 

 mina ; is insoluble in ammonia, but, like yttria, solu- 

 ble in carbonate of ammonia. 



Mr Davy has rendered it probable, that it is a me- 

 tallic peroxide. To the metallic basis he proposes to 

 give the name of glucium. 



SECT. IV. OfZirconia, 



, Zirconia was discovered by Klaproth in the two 

 a, , ,, , .' r . , . . . 



minerals called jargon or zircon, and the hyacinth. 



how <>b- Fuse the pounded mineral with thrice its weight of 

 taincd. potash ; wash the mass in pure water till tin- whole 

 of the potash it extracted, then dissolve the residuum 

 as far as possible in muriatic acid ; b>>il the solution, 

 filter and add a quantity of potash. The zirconia 

 pn-cipitatet. in the state of a fine powder. 



It oroo r- Zirconia is a white powder witha harsh feel. It has 

 f jg. neither taste nor odour, i infusiblt before the blow- 



pipe, but when violently heated, Acquires the appear- 

 aice of porcelain. In this state it is bard, aud its 



specific gravity it 4.3. It il insoluble in w*tcr, but, Klemea 

 when precipitated from a solution and dried slowly, 

 it retains water, and assumes the appearance of gum 

 arabic. 



It does not combine with oxygen, simple combus- 

 tibles, azote, nor metals. But it has an affinity for 

 several metallic oxides. 



It is insoluble in liquid alkalies, and infusible with 

 them ; but it is soluble in alkaline carbonates. 



Mr Davy has made it probable, that it is a metal- 

 lic peroxide. To the metallic basis he proposes to 

 give the name of zirconium. 



SECT. V. Of Silica. 



The minerals called quartz, rock-crystal, JJint, &c. silica, 

 consist almost entirely of this earth. It may be ob- 

 tained in the following manner. Melt in a crucible ni ^* 

 a mixture of one part quartz powder, and three parts tune ' 

 potash ; dissolve the mass in muriatic acid, and eva- 

 porate to dry ness ; towards the end of the evapora- 

 tion, the liquid assumes the form of a jelly ; wash 

 the residue in water, and dry it. 



Silica, thus obtained, is a fine white powder, with Its proper- 

 a harsh feel, and without either taste or smell. Its tie*, 

 specific gravity is 2.66. It has no effect on vege- 

 table colours, is insoluble in water, and infusible oy 

 the heat of our furnaces. It doet not form a ductile 

 paste with water, like alumina. It is found native 

 crystallized, most commonly in hexagonal prisms, 

 terminated by six-sided pyramids. 



It does not combine with oxygen, the simple com- 

 bustibles, simple incombustible*, or the metals. It 

 may be fused with several of the metallic oxides. 



The fixed alkalies may be fused with it into glass. 

 Ammonia has no action on it. It may be combined 

 with barytes, strontian, lime, and magnesia, by heat. 

 There is a strong affinity between it and alumina. 



Mr Davy has rendered it probable, that silica, like 

 the other earths, is a metallic peroxide. To the me- 

 tallic basis of it he proposes to give the name of si- 

 licium. 



CHAP. I. 

 Of Oxides. 



MANY bodies, as we have seen already, are capable 

 of combining with oxygen. Now, the compounds 

 into which oxygen enters are of two kinds. They 

 either possess the properties of acids, or they are 

 destitute of these properties. To the first class 'the Oxide ex- 

 term acid has been applied ; to the second that of 

 o.tulc. By oxide, then, is meant a combination of 

 oxygen and some other substance destitute of the 

 properties belonging to acids. It is very common to 

 find the same base combine with different doses of 

 oxypen, and form both acids and ojridrs. In all 

 these cases, the smaller proportion of oxygen con- 

 stitutes the oxide, and the larger the acid. Hence 

 it follows, that oxides always contain less oxygen 

 than acids with the same base. 



The oxides which we have to examine, are combi- 

 nations of oxygen with the simple combustibles aad 



