OYSTER PLANT 



OZONE 



water of it* own accord. It* flesh, though dark in 

 colour, is palatable. //. ni/H-nut is a Mack species 

 ranging from the Cape to tin- i anariea. Three or 

 four upeciea are confined to America, 



Oyster Plant. See SALSIFY. 



Ozirna ((Jr. o:e, 'a stench') in generally used 

 of all diseased conditions of the none accuni|ianicd 

 by great fetor of the lireath. Thin may arise from 

 toe ulceratioiiH occurring in tultercular or syphilitic 

 disease, or in lupus ; from malignant disease ; from 

 necrosed hone ; or from the pretence of a foreign 

 body. But it also occurs where none of these 

 cause* is present ; and to this form of disease the 

 term U limited by some recent writers ( Friinkel, 

 Morell Mackenzie, and others). In these cases 

 there is a peculiar form of inflammation of the 

 mucous membrane of the no-e, railed ilry nitnrrh, 

 in which the morhid secretion accumulates in the 

 form of crusts in the na-al cavity. Thin may 

 occasion comparatively little inconvenience, till it 

 leads, as it often does, to the occurrence of an 

 offensive and characteristic odour, the precise cause 

 of which has not been ascertained. It is a very 

 chronic and troublesome disease ; hut much relief 

 is obtained by the frequent use of alkaline and 

 antiseptic washes or sprays. An arrangement 

 devised by Gottstein renders the secretion moist, 

 ami so keeps the fetor in abeyance the intro- 

 duction of a plug of cotton-wool, which is worn in 

 each nostril for a few hours daily. 



O/niiain. AXTOINE FREDERIC, was brn at 

 Milan, April .':!, 1813, studied at Lyons and 1'iiris, 

 and was appointed in 1841 to fill the chair of 

 Foreign Literature at the Sorbonne. He died at 

 Marseilles, September s, 1S53. Uzanam possessed 

 learning ami industry, but fate did not favour him 

 in his dream of rivalling the work of ( -Hilton, 

 save in such fragments as Dante et la Philosophic 

 Catholique nit XIII' Siicle (1839), Hittoire de la 

 'ivttioH an V Stele (1845; Eng. trans. 1868), 

 and Kttula Gernuiniipie* (1847-49). A collected 

 edition of his writings fills 11 vols. (1862-75). 

 There are Lives by Karker ( Paderltorn, 1867), 

 OMeara (Eilin. 1876), and Hardy (Mainz, 1878). 



Ozokerite. See UITUMKN. 



Ozone Hlr. 0:6, 'I smell'). It was remarked 

 long ago that a peculiar odour was produced by 

 the working of an electrical machine. Van Maruiii 

 found that, when electric sparks were passed 

 through a tube containing oxygen, the gas became 

 ]Mi\verfully impregnated with tins odour which he 

 therefore called the 'smell of electricity.' Sub- 

 sequent writers attributed the phenomenon to the 

 formation of nitric acid, due to a trace of nitrogen 

 mixed with the oxygen ; especially as the gas was 

 found to act energetically u|ton mercury. Thus 

 supposed to be explained, these curious results 

 were soon forgotten. Hut in 1840 Schonltein (q.v.) 

 with remarkable acuteiiess made a closer investiga- 

 tion of the '|iie-: ion, and arrived at many most 

 curious result", all of which have not even yet 

 lieen satisfactorily accounted for. The problem 

 remain-, in fart, one of the mint perplexing, as 

 well as interesting, questions imperfectly icsolved 

 in chemistry. The e.ulier results of Schcinbein were 

 these: (1) When water is dccumpo-ed by the vol- 

 taic current, the electrodes lieing of gold or plati- 

 num, the oxygen (which appears at the positive 

 pole) possesses in a high degree the smell and the 

 oxidi-iug power developed bv Van Marum bv means 

 of friction-electricity. (2) When the positive elec- 

 trode if formed of an oxidUable metal these 



result* are not observed, but the electrode is 

 rapidly oxidised. (3) The oxygen collected at a 

 platinum electrode retains these properties for an 

 indefinite period if kept in a closed vessel : but 

 loses them by heating, by the contact of an oxidis- 

 able substance, and even by contact with such 

 Unties as charcoal and oxide of manganese. To 

 the sub-tancc. whatever it may be, which possesses 

 such powerful chemical allinitics, Schonltein gave 

 the name ozone, from its smell. In 1845 he showed 

 that the same substance can lie produced bv the 

 action of phosphorus on moi-t air, and hinted that 

 it might be a higher oxide of hydrogen. 



De la Rive and Marignac shortly afterwards, 

 repeating the experiments of Van Marum, .-bowed 

 that electric sparks produce ozone even in jnirc and 

 dry oxygen, and came to the conclusion that 

 ozone is oxygen in an allotronic state, as diamond 

 is a form of coke or charcoal, liaiimert, in 1853, 

 endeavoured to show that there are two kinds of 

 o/one one formed from pure oxygen by electric 

 sparks, which he allowed to be aflotropic oxvgcn ; 

 tlie other formed in the voltaic decomposition of 

 water, which he endeavoured to prove to be a 

 teroxide of hydrogen. Andrews, in 1856, refuted 

 this view, by showing that no such oxide of hydro- 

 gen (at least in a gaseous form) is produced in the 

 electrolysis of water; and that ozone, from what- 

 ever source obtained, is the same bod}', and is not 

 a compound, but an allotropic form of oxygen. 



In 1860 Andrews and Tait published ihe lesiilts 

 of a series "of volumetric experiments on this sub- 

 ject, which led to some remarkable conclusions 

 among which are the following : When the electric 

 discharge is passed through pure oxygen it con- 

 tiin-ts, hence ozone must be denser than oxygen. 

 A much greater amount of contraction, and a corre- 

 spondingly greater quantity of ozone, are produced 

 by a silent discharge of electricity between line 

 points than by a brilliant series of sparks. The 

 contraction due to the formation of the ozone is 

 entirely removed by the destruction of the ozone 

 by heat ; and this process can be repeated indefi- 

 nitely on the same portion of oxygen. 



Soret subsequently determined the density of 

 ozone as compared with that of oxygen, first by 

 absorbing the ozone from the oxygen with which 

 it was mixed by means of oil of turpentine or oil 

 of cinnamon, and observing the contraction pro- 

 duced ; and later by determining the relative i 

 of diffusion of chlorine and ozone. He ascertained 

 that its density i-- one and a half limes that of 

 oxygen. Andrews showed later that ozone is 

 rapidly destroyed when shaken np with dry frag- 

 ments of glass, &c. He also proved that the effect 

 which is (almost invariably, and sometimes in fine 

 weather powerfully) produced by the air on what 

 are called ozone test puiicrs papers steeped in 

 iodide of potassium which are rendered blown by 

 the liltcration of iodine i- really due to o/one. 

 He did so by showing that it acts upon mercury 

 as ozone does, and that it is destroyed by heat at 

 lie temperature. 



The quantity of ozone in the atmosphere is never 

 great, anil it varies within wide limits. Little or 

 nothing is known as to its function in the air, but 

 it is believed to be active in destroying unwhole- 

 some substances, owing to its intensely oxidising 

 properties. Ozone has l>een liquefied by the appli- 

 cation of pressure, at a temperature of about - 23 

 C. It is stated to lie blue in the liquid state, and 

 to be liable to decomposition into oxygen, with ex- 

 plosive violence, on sudden diminution of pressure. 



