OXYHYDROGEN 



heated to a dull redness in the air. 

 HI-IK f, l.y .ilit mutely forming and 

 loosing the barium ill.. \nli-, 

 the same quantity of barium salt 

 can be used over and over again 

 (5) The preparation of oxygen 

 from liquid air depends upon the 

 fact that the two chief constituent 

 liquid trap's, nitrogen and n 

 evajMirato at different temp. M 

 nitrogen lx>ing more volatile 

 than oxygen. Methods of separ- 

 ating them \\hirh ure worked on 

 scale have been devised, 

 Liquid air was first prepared by 

 Sir .lames Dewar, and the appar- 

 atus for manufacturing it on a large 

 scale was devised by Hampson. 



The production of oxygen from 

 liquid air by the Linde-Hampson 

 met litxl is illustrated diagrammatic- 

 ally on the previous page. A is a 

 wooden container ; B a rectifying 

 column down which liquid air 

 trickles when formed from plates 

 666 into receiver C ; D is an 

 inlet for compressed air which 

 traverses the small tube coils d, d, 

 d, and coil d 1 to expansion valve E, 

 thence by d* through funnel mouth 

 into the column B, thence partly 

 into funnel and pipe d 3 to coil F 

 and out at F 1 , and partly through 

 funnel and pipe G into interchange 

 coil H and out at H 1 . Nitrogen is 

 withdrawn through pipe G and 

 oxygen as vapour through d 3 and 

 D. J is a regulating hand-wheel of 

 the expansion valve E. 



(6) Other methods of preparing 

 oxygen may be summarised. The 

 peroxides or perborates of sodium 

 or other alkalis give off oxygen 

 when moistened with water, especi- 

 ally if they are previously mixed 

 with a catalyst. This method is 

 employed for producing oxygen 

 under the name of " oxylith," and 

 also in preparing tablets and salts 

 used for oxygen baths. When a 

 concentrated solution of bleaching 

 powder to which a little cobalt 

 oxide has been added is heated, 

 oxygen is given off. Oxygen is 

 also evolved from peroxide of 

 hydrogen, especially when it is 

 acidified with sulphuric acid and 

 a solution of potassium per- 

 manganate is added gradually. 

 Oxygen is employed in medicine 

 in cases of pneumonia and for 

 supplying oxygen to confined 

 spaces, e.g. in submarines and coal 

 mines, and for divers. Maturing 

 wines and obtaining high-tempera- 

 ture flame are other uses. Oxygen 

 is supplied on a commercial scale 

 compressed into steel cylinders of 

 various sizes, small ones being 

 available for medicinal oxygen, 

 and larger ones for use with search- 

 lights or optical lanterns. See 

 Atmosphere ; Combustion ; Hydro- 

 gen ; Ozone. 



09 13 

 Oxyhydrogen Flame. ' 



anil hydn.^.n liurnt t 

 HjM'ciiil jet. A flame of very high 

 temperature U so obtained, in 

 refractory metal* such aa pint mum 

 can be readily melted. A l.low- 

 pipe arrangement U used to obtain 

 the highest temperatures, the 



Oxyhydrogen Flame. Sectional dia- 

 gram ol blow-pipe used to produce 

 flame. 0. Oxygen ad minion. H. 

 Hydrogen ad million, a, b. Studi 

 keeping oxygen pipe central, e. 

 Gas-mixing chamber. D. Lime 

 cylinder rendered incandescent 



two gases being kept separate up 

 to the point of the jet, where they 

 are ignited. Autogenous soldering, 

 for which the Oxyhydrogen flame 

 was formerly employed, is now 

 done with thermite. When the oxy- 

 hydrogen flame is allowed to im- 

 pinge on a cylinder of lime an 

 intense white light is obtained, 

 known as the limelight, or Drum- 

 mond light. See Magic Lantern. 



Oxyrhynchus. Ancient town 

 near Behnesa, on the Bahr Yusuf, 

 Upper Egypt. The Egyptian name 

 was Permazet. The oxyrhynchus 

 (" sharp-snouted ")fish( Jformynw) 

 was venerated in the vicinity. In 

 the 5th century the town had 12 

 churches, 10,000 monk*, and 12,000 

 nuns. See Egypt Exploration 

 Society; Papyri. 



Oxytropis. Genus of perennial 

 herbs and shrubs of the natural 

 order Leguminosae. They are 

 natives of Europe, Asia, and N. 

 America. The leaves are divided 

 into two rows of leaflets. The 

 flowers are pea-like, purple, white, 

 or pale yellow, grouped in spikes 

 or sprays. 



Oyaxna, IWAO, PRINCE (1842- 

 1916). Japanese soldier. He 

 visited Europe during the Franco- 

 Prussian War, and in the Civil War 

 of 1877 led a brigade of the Im- 

 perial army. During the war with 

 China, 1894-95, he commanded the 

 second army, whose exploits in- 

 cluded the taking of Port Arthur 

 and Wei-hai-wei. In the Russo- 

 Japanese War, 1904-5, now mar- 

 quess and a field-marshal, he was in 

 chief command. His skilful con- 

 duct of operations, notably at the 

 battles of Liao-Yang, Shaho, and 

 Mukden, brought him the title of 

 prince in 1907. The year before he 

 had received the British Order of 

 Merit. He died Dec. 12, 1916. 



Oyapoc. River of S. America. 

 It rises in the Tumac Humac Mts.. 

 and flows N.E. to the Atlantic 

 Ocean, forming the E. frontier of 

 French Guiana. On its upper 



OYSTER 



coune are the Matouchi Falls, 

 while i.i|.nU interfere with navi 

 i I to length U 280 in. Oyapoc 

 village, 25 m. from the sea, trade* 

 in mlilMT, batata, and gold. 



Oyer and Terminer. Anglo 

 I'n-tic h legal term meaning to hear 

 and determine. In England 

 court* of assize rit by virtue of the 

 . commission issued by the king to 

 the persons therein named, one of 

 whom, at least, is always a judge.to 

 hear and determine all causes, and 

 to deliver all gaols of the prisoners 

 there awaiting trial for all tin- 

 sons, felonies, and misdemeanours. 

 Sometimes special commissions 

 are issued, as when there have been 

 serious riots. 



Oyster (0trea). Genus of bi- 

 valve mollusc*. Over 100 recent 

 species and over 500 extinct ones 

 are known to science. In the edible 

 oyster (O. edulis), common round 

 the British coasts, the valves of the 

 shell are unequal, the left valve 

 by which the animal is attached 

 to the rock being the larger and 

 concave, while the right valve is 

 thinner and nearly flat. The 

 exterior of the shell is rough and 

 irregular, notably the left valve, 

 and the interior is white and pearly. 



Unlike most of the bivalves, the 

 oyster having taken to a sedentary 

 life lacks the tough muscular foot ; 

 and the delicacy of the animal's 

 Hr.sh is partly due to this fact. 

 There is also only one nearly central 

 muscle a modified posterior one 

 for closing the shell, instead of 

 the anterior and posterior ones 

 usual in the Pelecypoda. The 

 mantle edges, with which the gills 

 are concrescent, are open all 

 round, and there are thus no 

 syphons. For this reason the 

 oyster can only feed by lying with 

 its valves slightly open, when the 

 minute organisms on which it sub- 

 sists are brought to its mouth by 

 current movements in the sur- 

 rounding water. Eyes of a simple 

 character are arranged along the 

 edges of the mantle, but how far 

 the oyster can see is unknown. 

 It is, however, very sensitive 

 to the change from darkness to 

 light. 



The oyster is extremely prolific, 

 producing from 600,000 to over 

 1,800,000 eggs in the season, 

 while one American species of 

 oyster is estimated to produce 

 100,000,000 ova. The spawning 

 time is from May till August, during 

 \\hii h the oyster is out of season. 

 The ova pass from the ovary to the 

 folds of the mantle edges, where 

 they hatch out, and the young are 

 periodically discharged as a cloud 

 of spat. At this period, known as 

 the glochidium or veliger stage, 

 the young swim freely in the water 



