ION 



411 



iRO 



by evolution. 2. In grammar, the in- 

 sertion of one or more clauses or members 

 of a sentence between the agent or sub- 

 ject and the ^rb. 



IOD'IC ACID, an acid formed by the oxy- 

 genation of Iodine. It is white and semi- 

 transparent, of a strong acid and astringent 

 taste, and destitute of smell. Its combi- 

 nations are termed iodates. 



I'ODIKE, from mSw, violet-coloured A 

 simple body accidentally discovered in 

 1812, by De Courtois, a manufacturer of 

 saltpetre at Paris, in the mother- waters 

 of that salt. Its affinities for other sub- 

 stances are so powerful as to prevent it 

 from existing in an insulated state. It 

 occurs, combined with potassium and 

 sodium, in many mineral waters, and 

 strongly saline springs. This combination 

 exists sparingly in sea- water, abundantly 

 in many species of/ueu* or sea-weed, and 

 in kelp made from them ; in springs, in 

 several marine molluscae,such as the doris 

 and oyster ; in several polyparies and sea- 

 plants ; particularly in the mother- waters 

 of the salt-works upon the Mediterranean 

 sea, and it has been found in combination 

 with silver in some ores brought from the 

 neighbourhood of Mexico. It is econo- 

 mically procured from the mother- water 

 of kelp, as furnished by those manufac- 

 turers of soap who employ this crude 

 alkali. By pouring an excess of sulphuric 

 acid upon that liquid, and exposing the 

 mixture to heat in a retort, iodine rises 

 in violet vapours, and condenses in the 

 receiver into black, brilliant, soft, scaly 

 crystals, resembling graphite or plum- 

 bago. 



I'ODO-NITRIC ACID, \ When sul- 



I'ODO-PHOSPHOR'IC ACID, > phuric acid is 



I'OPO-SULPHU'RIC ACID. ; dropped into 

 a concentrated and hot aqueous solution 

 of iodic acid, there immediately results a 

 precipitate of iodosulphuric acid, possessed 

 of peculiar properties. Analogous acids 

 are produced by the action of the nitric 

 and phosphoric acid on iodine. These 

 acids act powerfully on the metals, and 

 lissolve gold and platina. 



I'ODOUS ACID, an acid readily obtained 

 oy distilling equal parts of chlorate of 

 potash and iodine. It contains less oxygen 

 than the iodic acid. 



ION'IC ORDER. In architecture, an order 

 invented by the lonians as a medium be- 

 tween the masculine strength of the 

 Doric and the feminine slenderness of the 

 Corinthian. The capital has two spirals 

 peculiar to this order, in imitation of 

 ringlets of hair, and the cymation indi- 

 cates locks hanging over the forehead, 

 and the mouldings of the base represent 

 the turn and shape of shoes worn by fe- 

 males when the order was invented. The 

 body of the column is usually channelled 



with 24 gutters, and its length, with the 

 capital and bases, i* 2& modules. 



IPECACUAN'HA, Ipecantan. According 

 to Decandolle, the term ipecacuanha im- 

 plies in South America vomiting root ; and 

 therefore it is applied to the roots of very 

 different species of plants. The genera 

 which chiefly afford it are Viola, Cyna- 

 chum, Asclepias, Euphorbia, Dorstenia, 

 and Ruellia. The medicinal virtues of 

 ipecacuanha depend on the quantity of 

 hematine it contains. 



IP'SE DIX'IT (Lat.), he himself says. 



IP'SO FAC'TO (Lat.), by the deed itself. 



IRIDES'CENCE, exhibition of colours like 

 those of the rainbow (iris). 



IRID'IUM, a new metal procured from 

 crude platinum, along with osmium, and 

 thus named from iris, a rainbow, on ac- 

 count of the variety of colours which its 

 solutions exhibit. Iridium is the most 

 refractory of all the metals, and appears 

 as a grey metallic powder. 



IRON, Sax. iren, Scot. irne. The most 

 useful and the most plentiful of all the 

 metals. Its tenacity exceeds that of any 

 other metal known, and it is the hardest 

 of those which are malleable and ductile. 

 Its ores are found in all parts of the world, 

 in every mineral formation, and in every 

 soil. Mineralogists enumerate 19 species 

 or varieties, of which 10 are worked 

 either for the sake of the iron which they 

 contain, for use in a native state, or for 

 extracting some principles from them 

 useful in arts and manufactures ; such are 

 arsenical iron, sulphate of iron, sulphuret 

 of iron, and chromate of iron. Iron in a 

 state of carburet forms plumbago, cast- 

 iron, and steel. It is reduced from its ore* 

 by the process of smelting, and run out of 

 the furnace into sand-moulds of the pat- 

 tern required, or simply into furrows made 

 in sand : the large mass in the main fur- 

 row is termed by the workmen a sow, and 

 the less masses pigs, and hence the ge- 

 neral name of pig for crude iron. Wrought 

 iron is again prepared from the pig-iron, 

 by remelting and hammering, and this, 

 heated in contact with a cement of ground 

 charcoal and common salt, forms st*et. 

 The common iron ores of this countrv -.are 

 carbonates of iron, principally found in 

 the coal measures in connection with coal 

 and limestone, both of which are neces- 

 sary in the process of smelting. 



IRON-CLAY, a basaltic mineral usually 

 vesicular and of a reddish-brown colour. 



IRON-FLINT, a silicate of iron found both 

 massive and crystallised in six-sided 

 prisms. 



IRON LIQUOR, acetate of iron used as 

 mordant by dyers, Ac. 



IRON -WOOD. In botany, a name com- 

 mon to all the species of the genus Sider- 

 oxylon (q. v.) The wood is of a reddish 

 colour, and remarkable for its great spe- 



2 D 



