Oxygen sentence example
The noise from the machine that circulated the oxygen frightened her.
A blue haired old lady with a walker and her mate hauling an oxygen tank looked at me as If I was the Boston strangler.
Although the route was relatively flat by Colorado standards, Dean learned that a body unaccustomed to elevation in the 7,000foot range needed more oxygen to fuel its muscles.
By the time they finished erecting the oxygen tent over her bed, she had finally settled down.
Even so, it was as if a something had been lifted from her chest, allowing the flow of oxygen and blood to a starving brain.Advertisement
Even their oxidation, however, is effected by the protoplasm acting as an oxygen carrier.
There is no direct connection between the two, the oxygen is absorbed almost immediately by the protoplasm, and appears to enter into some kind of chemical union with it.
Humans require relatively little oxygen, and plants are constantly transforming the carbon dioxide we exhale back into useful oxygen.
The doctor said they could find no reason for him to stay in a coma, except the possibility of brain damage from lack of oxygen or blood loss.
They result from the cobaltammines by the direct taking up of oxygen and water.Advertisement
Nauseous from panic, I elbowed my way close enough to see a female figure, her face covered with an oxygen mask.
The supply of oxygen to a plant is thus seen to be as directly connected with the utilization of the energy of a cell as is that of food concerned in its nutrition.
Carmen gazed down at Destiny inside the oxygen tent.
In other words "fermentation is life without air, or life without oxygen."
It may lead to an incipient asphyxiation, as the supply of oxygen may be greatly interfered with and the escape of carbon dioxide may be almost stopped.Advertisement
Considerations of weight had long prevented Lavoisier from accepting this doctrine, but he was now able to explain the process fully, showing that the hydrogen evolved did not come from the metal itself, but was one product of the decomposition of the water of the dilute acid, the other product, oxygen, combining with the metal to form an oxide which in turn united with the acid.
His first original paper (1799) was on the compounds of arsenic and antimony with oxygen and sulphur, and of his other separate investigations one of the most important was that on the compound ethers, begun in 1807.
Theoretical speculations were revived by Lavoisier, who, having explained the nature of combustion and determined methods for analysing compounds, concluded that vegetable substances ordinarily contained carbon, hydrogen and oxygen, while animal substances generally contained, in addition to these elements, nitrogen, and sometimes phosphorus and sulphur.
Thus oxygen varies according as whether it is linked to hydrogen (hydroxylic oxygen), to two atoms of carbon (ether oxygen), or to one carbon atom (carbonyl oxygen); similarly, carbon varies according as whether it is singly, doubly, or trebly bound to carbon atoms.
Haemoglobin is composed of a basic albumin and an acid substance haematin; it combines readily with oxygen, carbon dioxide and carbon monoxide to form loose compounds.Advertisement
The volume of the hydrogen was about double that of the oxygen, and, since this is the ratio in which these elements are combined in water, it was concluded that the process con sisted essentially in the decomposition of water.
Lead combines with oxygen to form five oxides, viz.
Bismuth, the strongest of the diamagnetics, has a negative susceptibility which is numerically 20 times less than that of liquid oxygen.
It dissociates when heated to a high temperature and is not affected by oxygen.
For instance, if oxygen and hydrogen combine to form water, we have no experimental evidence that the molecule of oxygen is not in the very same place with the two molecules of hydrogen.Advertisement
The term is more customarily given to productions of flame such as we have in the burning of oils, gas, fuel, &c., but it is conveniently extended to other cases of oxidation, such as are met with when metals are heated for a long time in air or oxygen.
Hydrogen gas readily burns in oxygen or air with the formation of water.
It obviously attains its maximum in the case of the firing of pure "oxyhydrogen" gas (a mixture of hydrogen with exactly half its volume of oxygen, the quantity it combines with in becoming water,, German Knall-gas).
The study of calcination and combustion during the 17th and 18th centuries culminated in the discovery that air consists chiefly of a mixture of two gases, oxygen and nitrogen.
Thus, the gases are not present in simple multiples of their combining weights; atmospheric air results when oxygen and nitrogen are mixed in the prescribed ratio, the mixing being unattended by any manifestation of energy, such as is invariably associated with a chemical action; the gases may be mechanically separated by atmolysis, i.e.Advertisement
Bunsen analysed fifteen examples of air collected at the same place at different times, and found the extreme range in the percentage of oxygen to be from 20.97 to 20.84.
As the current flows it decomposes the liquid and liberates oxygen and hydrogen gases, which escape.
It combines directly with most elements, including nitrogen; this can be taken advantage of in forming almost a perfect vacuum, the oxygen combining to form the oxide, CaO, and the nitrogen to form the nitride, Ca 3 N 2.
It does not support combustion; and it does not burn readily unless mixed with oxygen, when it burns with a pale yellowish-green flame.
Bunsen showed that no oxygen was present.Advertisement
The ultimate source of the oxygen may be the air, as in the Bessemer process, or rich iron oxide as in the puddling process, or both as in the open-hearth process; but in any case iron oxide is the chief immediate source, as is to be expected, because the oxygen of the air would naturally unite in much greater proportion with some of the great quantity of iron offered to it than with the small quantity of these impurities.
As an illustration it may be pointed out that in the case of the two known types of lactones - the y-lactones, which contain four carbon atoms and one oxygen atom in the ring, are more readily formed and more stable (less readily hydrolysed) than the S-lactones, which contain one oxygen and five carbon atoms in the ring.
The elements which go to form heterocyclic rings, in addition to carbon, are oxygen, sulphur, selenium and nitrogen.
The three primary members are furfurane, thiophene and pyrrol, each of which contains four methine or CH groups, and an oxygen, sulphur and imido (NH) member respectively; a series of compounds containing selenium is also known.
Six-membered ring systems can be referred back, in a manner similar to the above, to pyrone, penthiophene and pyridine, the substances containing a ring of five carbon atoms, and an oxygen, sulphur and nitrogen atom respectively.Advertisement
He applied himself more particularly to the oxygen compounds, and determined with a fair degree of accuracy the ratio of carbon to oxygen in carbon dioxide, but his values for the ratio of hydrogen to oxygen in water, and of phosphorus to oxygen in phosphoric acid, are only approximate; he introduced no new methods either for the estimation or separation of the metals.
In his earlier experiments he burned the substance in a known volume of oxygen, and by measuring the residual gas determined the carbon and hydrogen.
Oxygen, recognized by its power of igniting a glowing splinter, results from the decomposition of oxides of the noble metals, peroxides, chlorates, nitrates and other highly oxygenized salts.
The end d is connected to an air or oxygen supply with an intermediate drying apparatus.
After having previously roasted the tube and copper oxide, and reduced the copper spiral a, the weighed calcium chloride tube and potash bulbs are put in position, the boat containing the substance is inserted (in the case of a difficultly combustible substance it is desirable to mix it with cupric oxide or lead chromate), the copper spiral (d) replaced, and the air and oxygen supply connected up. The apparatus is then tested for leaks.Advertisement
If all the connexions are sound, the copper oxide is gradually heated from the end a, the gas-jets under the spiral d are lighted, and a slow current of oxygen is passed through the tube.
When there is no more absorption in the potash bulbs, the oxygen supply is cut off and air passed through.
The platinum is maintained at a bright red heat, either by a gas flame or by an electric furnace, and the vapour is passed over it by leading in a current of oxygen.
The critical volume of oxygen can be deduced from the data of the above table, and is found to be 29, whereas the experimental value is 25.
Thus a double bond of oxygen, as in the carbonyl group CO, requires a larger volume than a single bond, as in the hydroxyl group - OH, being about 12.2 in the first case and 7.8 in the second.Advertisement
Oxygen, nitrogen, hydrogen and carbon monoxide have the value 1.4; these gases have diatomic molecules, a fact capable of demonstration by other means.
Hydroxylic oxygen is obtained by subtracting the molecular refractions of acetic acid and acetaldehyde.
If the crystal structure be regarded as composed of 0 three interpenetrating point systems, one consisting of sulphur atoms, the second of four times as many oxygen atoms, and the third of twice as many potassium atoms, the systems being so arranged that the sulphur system is always centrally situated with respect to the other two, and the potassium system so that it would affect the vertical axis, then it is obvious that the replacement of potassium by an element of greater atomic weight would specially increase the length of w (corresponding to the vertical axis), and cause a smaller increase in the horizontal parameters (x and 1/ '); moreover, the increments would advance with the atomic weight of the replacing metal.
There is thus a minimum circulation in the greater depths causing there uniformity of temperature, an absence of the circulation of oxygen by other means than diffusion, and a protection of the sulphuretted hydrogen from the oxidation which takes place in homologous situations in the open ocean.
Rutherford, who showed that on removing oxygen from air a gas remained, which was incapable of supporting combustion or respiration.
Nitrogen may be obtained from the atmosphere by the removal of the oxygen with which it is there mixed.
The combination of nitrogen with oxygen was first effected by Cavendish in 1785, who employed a spark discharge.
Lovejoy at Niagara Falls, who passed atmospheric air, or air enriched with oxygen, about a high tension arc made as long as possible; but the company (the Atmospheric Products Company) was a failure.
It does not burn, but supports the combustion of heated substances almost as well as oxygen.
Nitrogen peroxide, NO 2 or N204, may be obtained by mixing oxygen with nitric oxide and passing the red gas so obtained through a freezing mixture.
Nitrogen is always being synthesized from the atmosphere (by plants, and by electrical discharges which combine nitrogen and oxygen), and this combined nitrogen is either utilized by land organisms or is washed down into the sea in the water of the rivers.
The quantities of oxygen and carbonic acid in the sea are nearly constant so far as we can determine.
Further, the ocean and the atmosphere stand in equilibrium with each other; if there is excess of carbonic acid anywhere in the sea it is absorbed by the atmosphere and vice versa, and so also with the oxygen.
Thus the hydroxyl mentioned above decomposes into water and oxygen, and the chlorine produced by the electrolysis of a chloride may attack the metal of the anode.
The water which bears the oxygen for respiration and the minute organisms upon which the Brachiopod feeds is swept into the mantle cavity by the action of the cilia which cover the arms, and the eggs and excreta pass out into the same cavity.
One main purpose of his spectroscopic inquiries was to answer the question whether the sun contains oxygen or not.
In practice this oxidation process is continued until the whole of the oxygen is as nearly as possible equal in weight to the sulphur present as sulphide or as sulphate, i.e.
In Carinthia the oxidizing process from the first is pushed on so far that metallic lead begins to show, and the oxygen introduced predominates over the sulphur left.
In small works the cupellation is finished in one furnace, and the resulting low-grade silver fined in a plumbago crucible, either by overheating in the presence of air, or by the addition of silver sulphate to the melted silver, when air or sulphur trioxide and oxygen oxidize the impurities.
When kept fused in the presence of air lead readily takes up oxygen, with the formation at first of a dark-coloured scum, and then of monoxide PbO, the rate of oxidation increasing with the temperature.
The Kassner process for the manufacture of oxygen depends upon the formation of calcium plumbate, Ca2Pb04, by heating a mixture of lime and litharge in a current of air, decomposing this substance into calcium carbonate and lead dioxide by heating in a current of carbon dioxide, and then decomposing these compounds with the evolution of carbon dioxide and oxygen by raising the temperature.
On ignition, it loses oxygen and forms litharge.
It is decomposed by heat into oxide, nitrogen peroxide and oxygen; and is used for the manufacture of fusees and other deflagrating compounds, and also for preparing mordants in the dyeing and calico-printing industries.
In the second series, to which greater importance is attached, measurements were made of the force exerted in a divergent field upon small balls of copper, silver and other substances, first when the balls were in air and afterwards when they were immersed in liquid oxygen.
If V is the volume of a ball, H the strength of the field at its centre, and re its apparent susceptibility, the force in the direction x is f= K'VH X dH/dx; and if K',, and are the apparent susceptibilities of the same ball in air and in liquid oxygen, K' Q -K'o is equal to the difference between the susceptibilities of the two media.
The susceptibility of air being known - practically it was negligible in these experiments - that of liquid oxygen can at once be found.
It appears, therefore, that liquid oxygen is by far the most strongly paramagnetic liquid known, its susceptibility being more than four times greater than that of a saturated solution of ferric chloride.
Mesosomatic segments furnished with large plate-like appendages, the 1st pair acting as the genital operculum, the remaining pairs being provided with branchial lamellae fitted for breathing oxygen dissolved in water.
In primitive forms the respiratory lamellae of the appendages of the 3rd, 4th, 5th and 6th, or of the 1st and 2nd mesosomatic somites are sunk beneath the surface of the body, and become adapted to breathe atmospheric oxygen, forming the leaves of the so-called lung-books.
Nascent hydrogen reduces them to primary alcohols, and phosphorus pentachloride replaces the carbonyl oxygen by chlorine.
It abolished the conception of life s an entity above and beyond the common properties of matter, and led to the conviction that the marvellous and exceptional qualities of that which we call " living " matter are nothing more nor less than an exceptionally complicated development of those chemical and physical properties which we recognize in a gradually ascending scale of evolution in the carbon compounds, containing nitrogen as well as oxygen, sulphur and hydrogen as constituent atoms of their enormous molecules.
Like Fe 2 0 3, the yellow oxide lost 48 parts of oxygen per Ur203 (= 864 parts) as water, while Ur 2 = 816 parts of metal remained.
These results were adopted until Peligot in 1840 discovered that Berzelius's (and Klaproth's) metal contains oxygen, and that his (Ur 2) 0 3 really is (U606) 03= 3U 2 0 3, where U= 120 is one equivalent weight of real uranium.
Dilute sulphuric acid attacks it but slowly; hydrochloric acid, especially if strong, dissolves it readily, with the formation, more immediately, of a hyacinthcoloured solution of U 2 C1 6, which, however, readily absorbs oxygen from the air, with the formation of a green solution of UC1 4, which in its turn gradually passes into one of yellow uranyl salt, U02.
This operation is no doubt intended to remove the oxygen diffused throughout the metal as oxide, part of it perhaps chemically by reduction of the oxide to metal, the rest by conveying the finely diffused oxide to the surface and causing it to unite there with the oxide scum.
The hot vapour produced combines with the oxygen of the air into white oxide, Sn02.
How much of the hydrogen and oxygen are in the hydroxylic (OH) form cannot be absolutely stated, but from the study of the acetates at least three hydroxyl groups may be assumed.
Assuming the above formula to represent guncotton, there is sufficient oxygen for internal combustion without any carbon being left.
The vapour mixed with oxygen or air is violently explosive.
It can be formed independently of cell activity, nor does it require oxygen.
Cellular activity and oxygen appear to be essential for its development; it is found usually in the cells of certain organs, or it may be deposited in the intercellular tissues.
Oxidation may be effected by the addition to the glass mixture of a substance which gives up oxygen at a high temperature, such as manganese dioxide or arsenic trioxide.
It is not found in the uncombined condition, but in combination with other elements it is, with perhaps the exception of oxygen, the most widely distributed and abundant of all the elements.
Disregarding the rarer elements, the metals not named so far may be said to be proof against the action of pure water in the absence of free oxygen (air).
Mercury, if pure, and all the "noble" metals (silver, gold, platinum and platinum-metals), are absolutely proof against water even in the presence of oxygen and carbonic acid.
A group (B), comprising copper, is, substantially, attacked only in the presence of oxygen or air.
Mercury, within XVIII.7 a a certain range of temperatures situated close to its boiling point, combines slowly with oxygen into the red oxide, which, however, breaks up again at higher temperatures.
All other metals, when heated in oxygen or air, are converted, more or less readily, into stable oxides.
The metals of the alkalis and alkaline earths, also magnesium, burn in sulphur vapour as they do in oxygen.
The remaining oxygen atom is aldehydic or ketonic, for the sugars combine with hydrocyanic acid, hydroxylamine and phenylhydrazine.
This disintegration is brought about chiefly by changes in temperature, and by the action of the rain, the oxygen, and the carbon dioxide of the air.
The oxygen of the air may also bring about chemical changes which result in the production of soluble substances removable by rain, the insoluble parts being left in a loosened state.
It has been found by experiment that plants need for their nutritive process and their growth, certain chemical elements, namely, carbon, hydrogen, oxygen, nitrogen, sulphur, phosphorus, potassium, magnesium, calcium and iron.
With the exception of the carbon and a small proportion of the oxygen and nitrogen, which may be partially derived from the air, these elements are taken from the soil by crops.
The oxygen, however, decreases with the depth, while the carbon dioxide increases.
At a red heat it evolves oxygen with the formation of potassium nitrite, which, in turn, decomposes at a higher temperature.
The anhydrous salt, when exposed to a red heat, breaks up into oxide, sulphur dioxide and oxygen.
Alumina and lime, for example, which cannot be reduced at ordinary furnace temperatures, readily give up their oxygen to carbon in the electric furnace, and then combine with an excess of carbon to form metallic carbides.
It oxidizes rapidly when exposed to air, and burns when heated in air, oxygen, chlorine, bromine or sulphur vapour.
Hydrogen and oxygen may also be produced electrolytically as gases, and their respective reducing and oxidizing powers at the moment of deposition on the electrode are frequently used in the laboratory, and to some extent industrially, chiefly in the field of organic chemistry.
Peters has found that with these methods the best results are obtained when ozone is employed in addition to electrolytic oxygen.
This principle more or less prevailed until it was overthrown by Lavoisier's doctrine that oxygen was the acid-producing element; Lavoisier being led to this conclusion by the almost general observation that acids were produced when non-metallic elements were burnt.
The existence of acids not containing oxygen was, in itself, sufficient to overthrow this idea, but, although Berthollet had shown, in 1789, that sulphuretted hydrogen (or hydrosulphuric acid) contained no oxygen, Lavoisier's theory held its own until the researches of Davy, Gay-Lussac and Thenard on hydrochloric acid and chlorine, and of Gay-Lussac on hydrocyanic acid, established beyond all cavil that oxygen was not essential to acidic properties.
In later years Berzelius renounced the " oxygen acid " theory, but not before Davy, and, almost simultaneously, Dulong, had submitted that hydrogen and not oxygen was the acidifying principle.
In formulating these facts Liebig at first retained the dualistic conception of the structure of acids; but he shortly afterwards perceived that this view lacked generality since the halogen acids, which contained no oxygen but yet formed salts exactly similar in properties to those containing oxygen, could not be so regarded.
In general, gases dissolve in it more readily than in water; loo volumes of alcohol dissolve 7 volumes of hydrogen, 25 volumes of oxygen and 16 volumes of nitrogen.
Morley determined the densities of hydrogen and oxygen in the course of his classical investigation of the composition of water.
Consequently when the insect dives, an air-bubble forms around it, a supply of oxygen is thus secured for breathing and the water is kept away from the spiracles.
In art-work of this nature the principal points to be looked to in depositing are the electrical connexions to the cathode, the shape of the anode (to secure uniformity of deposition), the circulation of the electrolyte, and, in some cases, the means for escape of anode oxygen.
The formation of the blue mud is largely aided by the putrefaction of organic matter, and as a result the water deeper than 120 fathoms is extraordinarily deficient in dissolved oxygen and abounds in sulphuretted hydrogen, the formation of which is brought about by a special bacterium, the only form of life found at depths greater than 120 fathoms in the Black Sea.
The elements in addition to oxygen which exist in largest amount in sea salt are chlorine, bromine, sulphur, potassium, sodium, calcium and magnesium.
The water of the ocean, like any other liquid, absorbs a certain amount of the gases with which it is in contact, and thus sea-water contains dissolved oxygen, nitrogen and carbonic acid absorbed from the atmosphere.
One portion is used for determining the oxygen and nitrogen, the other for the carbonic acid.
The oxygen is then absorbed by some appropriate means, and the volume of the nitrogen measured directly, that of the oxygen being given by difference.
Fox, of the Central Laboratory of the International Council at Christiania, has investigated the relation of the atmospheric gases to sea-water by very exact experimental methods and arrived at the following expressions for the absorption of oxygen and nitrogen by sea-water of different degrees of concentration.
Jacobsen on some occasions found water in the surface layers of the Baltic supersaturated with oxygen, which he ascribed to the action of the chlorophyll in vegetable plankton; in other cases when examining the nearly stagnant water from deep basins he found a deficiency of oxygen due no doubt to the withdrawal of oxygen from solution, by the respiration of the animals and by the oxidation of the deposits on the bottom.
The distribution of dissolved oxygen in the depths of the open ocean is still very imperfectly known.
Dittmar's analysis of the " Challenger " samples indicated an excess of oxygen in the surface water of high southern latitudes and a deficiency at depths below 50 fathoms.
The respiration of marine animals in the depths of deep basins in which there is no circulation adds to the carbonic acid at the expense of the dissolved oxygen.
They all contain carbon, hydrogen, oxygen and nitrogen, forming the carbonaceous or combustible portion, and some quantity of mineral matter, which remains after combustion as a residue or " ash."
The amount of hydrogen is from 42 to 6%, while the oxygen may vary within much wider limits, or from about 3 to 14%.
When coal is heated to redness out of contact with the air, the more volatile constituents, water, hydrogen, oxygen, and nitrogen are in great part expelled, a portion of the carbon being also volatilized in the form of hydro carbons and carbonic oxide,-the greater part, however, remaining behind, together with all the mineral matter or ash, in the form of coke, or, as it is also called, " fixed carbon."
The caking property is best developed in coals low in oxygen with 25 to 30% of volatile matters.
The newer forms are based upon the principle, first enunciated by Professor Theodor Schwann in 1854, of carrying compressed oxygen instead of air, and returning the products of respiration through a regenerator containing absorptive media for carbonic acid and water, the purified current being returned to the mouth with an addition of fresh oxygen.
In another form of apparatus advantage is taken of the property possessed by sodium-potassium peroxide of giving off oxygen when damped; the residue of caustic soda and potash yielded by the reaction is used to absorb the carbonic acid of the expired air.
Caesium nitrate, CsNO 3, is obtained by dissolving the carbonate in nitric acid, and crystallizes in glittering prisms, which melt readily, and on heating evolve oxygen and leave a residue of caesium nitrite.
Although at the present time a marvellous improvement has taken place all round in the quality of the carbide produced, the acetylene nearly always contains minute traces of hydrogen, ammonia, sulphuretted hydrogen, phosphuretted hydrogen, silicon hydride, nitrogen and oxygen, and sometimes minute traces of carbon monoxide and dioxide.
When acetylene was first introduced on a commercial scale attempts were made to utilize its great heat of combustion by using it in conjunction with oxygen in the oxy hydrogen blowpipe.
Angus Smith determined London air to vary in oxygen content from 20.857 to 20.95, the air in parks and open spaces showing the higher percentage; Glasgow air showed similar results, varying from 20.887 in the streets to 20 92 9 in open spaces.
In addition to nitrogen and oxygen, there are a number of other gases and vapours generally present in the atmosphere.
Sodium dioxide is chiefly employed as an oxidizing agent, being used in mineral analysis and in various organic preparations; it readily burns paper, wood, &c., but does not evolve oxygen unless heated to a high temperature.
They are strong oxidizing agents and yield alkaline solutions which readily evolve oxygen on heating.
Sodium trioxide, Na 2 O 31 is said to be formed from an excess of oxygen and a solution of sodammonium in liquid ammonia.
Water decomposes it, giving oxygen and the dioxide.
In combination with oxygen (as carbon dioxide) it is also found to a small extent in the atmosphere.
It burns when heated in an atmosphere of oxygen, forming carbon dioxide, and when heated in sulphur vapour it forms carbon bisulphide.
The volume composition of carbon monoxide is established by exploding a mixture of the gas with oxygen, two volumes of the gas combining with one volume of oxygen to form two volumes of carbon dioxide.
It is a constituent of the minerals cerussite, malachite, azurite, spathic iron ore, calamine, strontianite, witherite, calcite aragonite, limestone, &c. It may be prepared by burning carbon in excess of air or oxygen, by the direct decomposition of many carbonates by heat, and by the decomposition of carbonates with mineral acids, M2C03+2HC1=2MCl-FH 2 O+CO 2.
The volume composition of carbon dioxide is determined by burning carbon in oxygen, when it is found that the volume of carbon dioxide formed is the same as that of the oxygen required for its production, hence carbon dioxide contains its own volume of oxygen.
Perfectly dry oxygen, however, has no action upon it.
At a white heat the vapour breaks down into potassium, hydrogen and oxygen.
The peroxide, K204, discovered by Gay-Lussac and Thenard, is obtained by heating the metal in an excess of slightly moist air or oxygen.
It is a dark yellow powder, which fuses at a high temperature, the liquid on cooling depositing shining tabular crystals; at a white heat it loses oxygen and yields the monoxide.
The solution is strongly caustic. It turns yellow on exposure to air, absorbing oxygen and carbon dioxide and forming thiosulphate and potassium carbonate and liberating sulphuretted hydrogen, which decomposes into water and sulphur, the latter combining with the monosulphide to form higher salts.
Its therapeutic action is said to be due to nascent oxygen given off, so it is local in its action.
In the following year he showed that plumbago consists essentially of carbon, and he published a record of estimations of the proportions of oxygen in the atmosphere, which he had carried on daily during the whole of 1778 - three years before Cavendish.
The former, "fire-air," or oxygen, he prepared from "acid of nitre," from saltpetre, from black oxide of manganese, from oxide of mercury and other substances, and there is little doubt but that he obtained it independently a considerable time before Priestley.
They are decomposed on heating, with liberation of oxygen, in some cases leaving a residue of iodide and in others a residue of oxide of the metal, with liberation of iodine as well as of oxygen.
It dissolves gold (q.v.) in the presence of water and atmospheric oxygen.
Henry Draper's most important contributions to science were made in spectroscopy; he ruled metal gratings in 1869-1870, made valuable spectrum photographs after 1871, and proved the presence of oxygen in the sun in a monograph of 1877.
To obtain a good reducing flame (in which the combustible matter, very hot, but not yet burned, is disposed to take oxygen from any compound containing it), the nozzle, with smaller orifice, should just touch the flame at a point higher above the wick, and a somewhat weaker current of air should be blown.
Blowpipes in which oxygen is used as the blast have been manufactured by Fletcher, Russell && Co., and have proved of great service in conducting fusions which require a temperature above that yielded by the air-blowpipe.
Heated with concentrated hydrochloric acid it liberates chlorine, and with sulphuric acid it liberates oxygen.
Chromous chloride, CrC1 2, is prepared by reducing chromic chloride in hydrogen; it forms white silky needles, which dissolve in water giving a deep blue solution, which rapidly absorbs oxygen, forming basic chromic salts, and acts as a very strong reducing agent.
A phosphide, PCr, is known; it burns in oxygen forming the phosphate.
Paschen 6 has further extended the method and added a number of infra-red lines to the spectra of helium, argon, oxygen and other elements.
The conclusion which was originally drawn from this fact that helium is a mixture of two gases has not been confirmed, as one of the spectra of oxygen is similarly constituted.
But a mixture of nitrogen and oxygen containing only little nitrogen will show the nitrogen lines narrow and similarly narrow oxygen lines may be obtained if the quantity of oxygen is reduced.
But that it may be given by the ordinary diatomic molecule is exemplified by oxygen, which gives in thick layers by absorption one of the typical sets of bands which were used by Deslandres and others to investigate the laws of distribution of frequencies.
These bands appear in the solar spectrum as we observe it, but are due to absorption by the oxygen contained in the atmosphere.
If oxygen is rendered luminous by the electric discharge, a series of spectra may be made to appear.
Under different conditions we obtain (a) a continuous spectrum most intense in the yellow and green, (b) the spectrum dividing itself into two families of series, (c) a spectrum of lines which appears when a strong spark passes through oxygen at atmospheric pressure, (d) a spectrum of bands seen in the kathode glow.
We have therefore five distinct spectra of oxygen apart from the absorption spectra of ozone.
In the light of our present knowledge we should look for the different behaviour in the peculiarity of the oxygen flame to ionize the metallic vapour.
In effect, therefore, Mayow - who also gives a remarkably correct anatomical description of the mechanism of respiration - preceded Priestley and Lavoisier by a century in recognizing the existence of oxygen, under the guise of his spiritus nitro-aereus, as a separate entity distinct from the general mass of the air; he perceived the part it plays in combustion and in increasing the weight of the calces of metals as compared with metals themselves; and, rejecting the common notions of his time that the use of breathing is to cool the heart, or assist the passage of the blood from the right to the left side of the heart, or merely to agitate it, he saw in inspiration a mechanism for introducing oxygen into the body, where it is consumed for the production of heat and muscular activity, and even vaguely conceived of expiration as an excretory process.
When heated in dry oxygen it becomes incandescent, forming magnesia.
It appears to his imagination that the affinity of two atoms of hydrogen to one of oxygen, the attraction of the spermatozoon to the ovum, and the elective affinity of d pair of lovers are all alike due to sensation and will.
Olszewski, and illustrated for the first time in public the liquefaction of oxygen and air, by means of apparatus specially designed for optical projection so that the actions taking place might be visible to the audience.
Soon afterwards he constructed a machine from which the liquefied gas could be drawn off through a valve for use as a cooling agent, and he showed its employment for this purpose'in connexion with some researches on meteorites; about the same time he also obtained oxygen in the solid state.
By 1891 he had designed and erected at the Royal Institution an apparatus which yielded liquid oxygen by the pint, and towards the end of that year he showed that both liquid oxygen and liquid ozone are strongly attracted by a magnet.
For gases such as oxygen and nitrogen dissolved in water the solubility as thus defined is independent of the pressure, or the mass of gas dissolved is proportional to the pressure.
Beyond variable quantities of moisture and traces of carbonic acid, hydrogen, ammonia, &c., the only constituents recognized were nitrogen and oxygen.
The analysis of air was conducted by determining the amount of oxygen present and assuming the remainder to be nitrogen.
Observations undertaken mainly in the interest of Prout's law, and extending over many years, had been conducted to determine afresh the densities of the principal gases - hydrogen, oxygen and nitrogen.
Under the influence of the heat the atmospheric oxygen unites with the hydrogen of the ammonia, and when the excess of the latter is removed with sulphuric acid, the gas properly desiccated should be pure nitrogen, derived in part from the ammonia, but principally from the air.
A few concordant determinations of density having been effected, the question was at first regarded as disposed of, until the thought occurred that it might be desirable to try also the more usual method of preparation in which the oxygen is removed by actual oxidation of copper without the aid of ammonia.
Subsequently when oxygen was substituted for air in the first method, so that all (instead of about one-seventh part) of the nitrogen was derived from ammonia, the difference rose to 2%.
Whatever were the means employed to rid air of accompanying oxygen, a uniform value of the density was arrived at, and this value was z% greater than that appertaining to nitrogen extracted from compounds such as nitrous oxide, ammonia and ammonium nitrite.
For this purpose I diminished a similar mixture of dephlogisticated [oxygen] and common air, in the same manner as before [by sparks over ], till it was reduced to a small part of its original bulk.
A convenient adjunct to this apparatus is a small voltameter, with the aid of which oxygen or hydrogen.
During this stage the oxygen should be in considerable excess.
When the yellow line of nitrogen has disappeared, and no further contraction seems to be in progress, the oxygen maybe removed by cautious introduction of hydrogen.
Water vapour and excess of oxygen in moderation do not interfere seriously with its visibility.
In one experiment, specially undertaken for the sake of measurement, the total air employed was 9250 c.c., and the oxygen consumed, manipulated with the aid of partially deaerated water, amounted to 10,820 c.c. The oxygen contained in the air would be 1942 c.c.; so that the quantities of atmospheric nitrogen and of total oxygen which enter into combination would be 7308 c.c. and 12,762 c.c. respectively.
This corresponds to N+1 7 5 0, the oxygen being decidedly in excess of the proportion required to form nitrous acid.
Into this air, previously deprived of oxygen by red-hot copper and thoroughly dried, is led in a continuous stream.
The volume actually weighed was 163 c.c. Subsequently large-scale operations with the same apparatus as had been used for the principal gases gave an almost identical result (19.940) for argon prepared with oxygen.
From the manner of its preparation it was clear at an early stage that argon would not combine with magnesium or calcium at a red heat, nor under the influence of the electric discharge with oxygen, hydrogen or nitrogen.
Conspicuous examples are afforded by oxygen, carbon, boron, silicon, phosphorus, mercuric oxide and iodide.
They are all decomposed when heated to a sufficiently high temperature, with evolution for the most part of oxygen and nitrogen peroxide, leaving a residue of oxide of the metal.
It may be noted that in a paper on the "Proportion of the gases or elastic fluids constituting the atmosphere," read by him in November 1802, the law of multiple proportions appears to be anticipated in the words - "The elements of oxygen may combine with a certain portion of nitrous gas or with twice that portion, but with no intermediate quantity," but there is reason to suspect that this sentence was added some time after the reading of the paper, which was not published till 1805.
The operation is essentially a dissociation of alumina into aluminium, which collects at the cathode, and into oxygen, which combines with the anodes to form carbon monoxide, the latter escaping and being burnt to carbon dioxide outside.
It is not magnetic. It stands near the positive end of the list of elements arranged in electromotive series, being exceeded only by the alkalis and metals of the alkaline earths; it therefore combines eagerly, under suitable conditions, with oxygen and chlorine.
This process, which is as yet imperfectly understood, is attended by the consumption of oxygen, the liberation of energy in the form of heat, and the exhalation of carbon dioxide and water vapour.
Sodium amalgam reduces them to secondary alcohols; phosphorus pentachloride replaces the carbonyl oxygen by chlorine, forming the ketone chlorides.
Like these, also, they respire oxygen, and are independent of light; and their various powers of growth, secretion, and general metabolism, irritability, and response to external factors show similar specific variations in both cases.
Oxygen, probably dissolved in the iron as ferrous oxide FeO, also makes the metal red-short.
With oxygen it probably forms manganous oxide, which is less harmful than ferrous oxide.
If the pig iron is to follow path 2, the purification which converts it into wrought iron or steel consists chiefly in oxidizing and thereby removing its carbon, phosphorus and other impurities, while it is molten, either by means of the oxygen of atmospheric air blown through it as in the Bessemer process, or by the oxygen of iron ore stirred into it as in the puddling and Bell-Krupp processes, or by both together as in the open hearth process.
The iron oxide thus formed immediately oxidizes these foreign elements, so that the iron is really a carrier of oxygen from air to impurity.
The oxygen of the blast having been thus taken up by the molten metal, its nitrogen issues from the mouth of the converter as a pale spark-bearing cone.
In making very low-carbon steel this recarburizing proper is not needed; but in any event a considerable quantity of manganese must be added unless the pig iron initially contains much of that metal, in order to remove from the molten steel the oxygen which it has absorbed from the; blast, lest this make it redshort.
Part of the carbon of this spiegeleisen unites with the oxygen occluded in the molten iron to form carbonic oxide, and again a bright flame, greenish with manganese, escapes from the converter.
A cold lump of ore chills the slag immediately around it, just where its oxygen, reacting on the carbon of the metal, generates carbonic oxide; the slag becomes cool, viscous, and hence easily made to froth, just where the froth-causing gas is evolved.
The two metallic masses coalesce, and the reaction between the oxygen of one and the carbon of the other is therefore extremely rapid because it occurs throughout their depth, whereas in common procedure oxidation occurs only at the upper surface of the bath of cast iron at its contact with the overlying slag.
Next comes the deoxidizing and desulphurizing stage, of which the first step is to throw some strongly deoxidizing substance, such as coke or ferro-silicon, upon the molten metal, in order to remove thus the chief part of the oxygen which it has taken up during the oxidation of the phosphorus in the preceding stage.
It is by forming calcium sulphide that sulphur is removed in the manufacture of pig iron in the iron blast furnace, in the crucible of which, as in the electric furnaces, the conditions are strongly deoxidizing But in the Bessemer and open-hearth processes this means of removing sulphur cannot be used, because in each of them there is always enough oxygen in the atmosphere to re-oxidize any calcium as fast as it is deoxidized.
Electric furnaces are at an advantage over others as regards the removal of sulphur and of iron oxide from the molten steel, because their atmosphere is free from the sulphur always present in the flame of coal-fired furnaces, and almost free from oxygen, because this element is quickly absorbed by the carbon and silicon of the steel, and in the case of arc furnaces by the carbon of the electrodes themselves, and is replaced only very slowly by leakage, whereas through the Bessemer converter and the open-hearth furnace a torrent of air is always rushing.
As we have seen, the removal of sulphur can be made complete only by deoxidizing calcium, and this cannot be done if much oxygen is present.
Indeed, the freedom of the atmosphere of the electric furnaces from oxygen is also the reason indirectly FIG.
It is practically unattainable in the open-hearth furnace, because here the oxygen of the furnace atmosphere indirectly oxidizes the carbon of the metal which is kept boiling by the escape of the resultant carbonic oxide.
In short the electric furnaces can be used to improve the molten product of the Bessemer converter and open-hearth furnace, essentially because their atmosphere is free from sulphur and oxygen, and because they can therefore remove sulphur, iron oxide and mechanically suspended slag, more thoroughly than is possible in these older furnaces.
It forms a highly explosive mixture with air or oxygen, especially when in the proportion of two volumes of hydrogen to one volume of oxygen.
Hydrogen combines with oxygen to form two definite compounds, namely, water (q.v.), H 2 O, and hydrogen peroxide, H202, whilst the existence of a third oxide, ozonic acid, has been indicated.
The alcohol is removed by distillation in vacuo, and by further concentration in vacuo a solution may be obtained which evolves 580 volumes of oxygen.
Hydrogen peroxide can also react as a reducing agent, thus silver oxide is reduced with, a rapid evolution of oxygen.
Potassium permanganate, in the presence of dilute sulphuric acid, is rapidly reduced by hydrogen peroxide, oxygen being given off, 2KM7,04+ 3H2S04+5H202= K2S04+2MnS04+8H20+502.
When Wohler, in 1825, analysed his cyanic acid, and Liebig his quite different fulminic acid in 1824, the composition of both compounds proved to be absolutely the same, containing each in round numbers 28% of carbon, 33% of nitrogen, 37% of oxygen and 2% of hydrogen.
These phenomena were quite in accordance with the atomic conception of matter, since a compound containing the same number of atoms of carbon, nitrogen, oxygen and hydrogen as another in the same weight might differ in internal structure by different arrangements of those atoms. Even in the time of Berzelius the newly introduced conception proved to include two different groups of facts.
It is probable that the whole phenomenon of isomerism is due to the possibility that compounds or systems which in reality are unstable yet persist, or so slowly change that practically one can speak of their stability; for instance, such systems as explosives and a mixture of hydrogen and oxygen, where the stable form is water, and in which, according to some, a slow but until now undetected change takes place even at ordinary temperatures.
This explains a good deal of the possible instability; and, from a practical point of view, it coincides with the fact that such a large amount of energy can be stored in our most intense explosives such as dynamite, the explanation being that hydrogen is attached to carbon distant from oxygen in the same molecule, and that only the characteristic resistance of the carbon linkage prevents the hydrogen from burning, which is the main occurrence in the explosion of dynamite.
In the divalent oxygen we meet with the modification called ozone, which, although unstable, changes but slowly into oxygen.
An early step accomplished by Ostwald in this direction is to define ozone in its relation to oxygen, considering the former as differing from the latter by an excess of energy, measurable as heat of transformation, instead of defining the difference as diatomic molecules in oxygen, and triatomic in ozone.
Experiments on the combustion of diamond were made by Smithson Tennant (1797) and Sir Humphry Davy (1816), with the object of proving that it is pure carbon; they showed that burnt in oxygen it yields exactly the same amount of carbon dioxide as that produced by burning the same weight of carbon.
The Curies showed that oxygen was convertible into ozone, and Sudborough that yellow phosphorus gave the red modification when submitted to their influence.
He selected the administration of tobaccos, addressing himself especially to chemical researches under the guidance of Gay-Lussac, and gave striking proof of ability in two papers on the combinations of phosphorus with hydrogen and oxygen, published in Annales de Chimie et de Physique (1835 and 1837).
Newly pressed rape oil has a dark sherry colour with, at first, scarcely any perceptible smell; but after resting a short time the oil deposits an abundant mucilaginous slime, and by taking up oxygen it acquires a peculiar disagreeable odour and an acrid taste.
Lanthanum oxide, La203, is a white powder obtained by burning the metal in oxygen, or by ignition of the carbonate, nitrate or sulphate.
In this way as the water sinks down through the porous subsoil or into the subterranean drains oxygen enters and supplies an element which is needed, not only for the oxidation of organic matters in the earth, but also for the direct and indirect nutrition of the roots.
In a fine state of division it takes fire on heating in air, but is permanent at ordinary temperatures in oxygen or air; it is readily attacked by hydrochloric and sulphuric acids, but scarcely acted on by nitric acid.
Out of a total of 146 auroral lines, with wave-lengths longer than 3684 tenth-metres, Westman identifies 82 with oxygen or nitrogen lines at the negative pole in vacuum discharges.
The interval considered by Westman contains at least 300 oxygen and nitrogen lines, so that approximate coincidence with a number of auroral lines was almost inevitable, and an appreciable number of the coincidences may be accidental.
Even small strips of the muscle of the heart, if taken immediately after the death of the animal, continue, when kept moist and warm and supplied with oxygen, to "beat" rhythmically for hours.
By an ingenious method devised by Engelmann, it may be shown that the greatest liberation of oxygen, and consequently the greatest assimilation of carbon, occurs in that region of the spectrum represented by the absorption bands.
The experiment of Engelmann referred to deserves to be mentioned here, if only in illustration .of the use to which algae have been put in the study of physiological problems. Engelmann observed that certain bacteria were motile only in the presence of oxygen, and that they retained their motility in a microscopic preparation in the neighbourhood of an algal filament when they had come to rest elsewhere on account of the exhaustion of oxygen.
After the bacteria had all been brought to rest by being placed in the dark, he threw a spectrum upon the filament, and observed in what region the bacteria first regained their motility, owing to the liberation of oxygen in the process of carbon-assimilation.
Thallic oxide, T1203, is obtained as a dark reddish powder, insoluble in water and alkalis, by plunging molten thallium into oxygen, or by electrolysing water, using a thallium anode.
Hydrochloric acid gives thallous chloride and chlorine; sulphuric acid gives off oxygen; and on heating it first gives the trioxide and afterwards the monoxide.
It becomes red on exposure, and in the moist condition absorbs oxygen from the air, giving alloxantin.
Oxygen occurs naturally as one of the chief constituents of the atmosphere, and in combination with other elements it is found in very large quantities; it constitutes approximately eight-ninths by weight of water and nearly one-half by weight of the rocks composing the earth's crust.
It is also disengaged by growing vegetation, plants possessing the power of absorbing carbon dioxide, assimilating the carbon and rejecting the oxygen.
Oxygen may be prepared by heating mercuric oxide; by strongly heating manganese dioxide and many other peroxides; by heating the oxides of precious metals; and by heating many oxy-acids and oxy-salts to high temperatures, for example, nitric acid, sulphuric acid, nitre, lead nitrate, zinc sulphate, potassium chlorate, &c. Potassium chlorate is generally used and the reaction is accelerated and carried out at a lower temperature by previously mixing the salt with about one-third of its weight of manganese dioxide, which acts as a catalytic agent.
Numerous methods have been devised for the manufacture of oxygen.
Oxygen is a colourless, odourless and tasteless gas.
For the properties of liquid oxygen see Liquid Gases.
It is found, more especially in the case of organic compounds, that if a substance which oxidizes readily at ordinary temperature be mixed with another which is not capable of such oxidation, then both are oxidized simultaneously, the amount of oxygen used being shared equally between them; or in some cases when the substance is spontaneously oxidized an equivalent amount of oxygen is converted into ozone or hydrogen peroxide.
The oxygen uniting with the substance undergoing oxidation is generally known as "bound oxygen," whilst that which is transformed into ozone or hydrogen peroxide is usually called "active oxygen."
Schonbein (loc. cit.) assumed that the ordinary oxygen molecule is decomposed into two parts which carry electrical charges of opposite kinds, the one with the positive charge being called "antozone" and the other carrying the negative charge being called "ozone," one variety being preferentially used up by the oxidizing compound or element and the other for the secondary reaction.
Traube (loc. cit.), on the other hand, concludes that the oxygen molecule enters into action as a whole and that on the oxidation of metals, hydrogen peroxide and the oxide of the metal are the primary products of the reaction.
Oxygen is a member of the sixth group in the periodic classification, and consequently possesses a maximum valency of six.
Villiger (Be y ., 1901, 34, pp. 2679, 3612) showed that many organic compounds (ethers, alcohols, aldehydes, ketones, &c.) behave towards acids, particularly the more complex acids, very much like bases and yield crystallized salts in which quadrivalent oxygen must be assumed as the basic element.
Walden point out from the physico-chemical standpoint that in water and hydrogen peroxide the oxygen atom is probably quadrivalent.
The atomic weight of oxygen is now generally taken as 16, and as such is used as the standard by which the atomic weights of the other elements are determined, owing to the fact that most elements combine with oxygen more readily than with hydrogen (see ELE Ment).
Oxygen is widely used in medical practice as well as in surgery.
Oxygen is also administered in chloroform poisoning, and in threatened death from the inhalation of coal gas or nitrous oxides.
The mode of administration is by an inhaler attached to an inhalation bag, which serves to break the force with which the oxygen issues from the cylinders in which it is sold in a compressed form.
Oxygen may be applied locally as a disinfectant to foul and diseased surfaces by the use of the peroxide of hydrogen, which readily parts with its oxygen; a solution of hydrogen peroxide therefore forms a valuable spray in diphtheria, tonsillitis, laryngeal tuberculosis and ozaena.
It is a hard black solid which readily loses oxygen when strongly heated, leaving a residue of Mn 3 0 4.
When heated with concentrated hydrochloric acid it yields chlorine, and with concentrated sulphuric acid it yields oxygen.
It is almost impossible to prepare a pure hydrated manganese dioxide owing to the readiness with which it loses oxygen, leaving residues of the type xMnO yMn0 2.
The metals, which by combination with oxygen became oxides, were antimony, silver, arsenic, bismuth, cobalt, copper, tin, iron, manganese, mercury, molybdenum, nickel, gold, platinum, lead, tungsten and zinc; and the "simple earthy salifiable substances" were lime, baryta, magnesia, alumina and silica.
It consists essentially of cinnamic aldehyde, and by the absorption of oxygen as it becomes old it darkens in colour and develops resinous compounds.
It is a bluish-green powder, which on exposure rapidly combines with the oxygen of the air.
This can be done most easily by " active " oxygen, such as is present in the peroxides, in chromic or permanganic acid.
The object of the latter is to convert the manganous hydroxide by the atmospheric oxygen into manganese dioxide, but this would take place much too slowly if there was not an excess of lime present ready to combine with the manganese dioxide to form a calcium manganite.
This " alkali-waste," also called tank-waste or vatwaste, was thrown into heaps where the calcium sulphide was gradually acted upon by the moisture and the oxygen of the air.
It is mixed with fresh air containing sufficient oxygen for the combustion of the hydrogen, and the mixture is passed through red-hot iron oxide (burnt pyrites) which by its catalytic action causes the reaction H2S+O= H 2 O+S to take place.
These are the external gills, through which the animal breathes the oxygen dissolved in the water.
Perceiving a molecular isonomy between them and the inorganic compounds of the metals from which they may be formed, he saw their true molecular type in the oxygen, sulphur or chlorine compounds of those metals, from which he held them to be derived by the substitution of an organic group for the oxygen, sulphur, &c. In this way they enabled him to overthrow the theory of conjugate compounds, and they further led him in 1852 to publish the conception that the atoms of each elementary substance have a definite saturation capacity, so that they can only combine with a certain limited number of the atoms of other elements.
They behave as unsaturated compounds, combining with oxygen to form peroxides and with the halogens to form triarylmethane halides.
Davy, on the other hand, could see no reason to suppose it contained oxygen, as they surmised, and ultimately they had to accept his view of its elementary character.
The proof that prussic acid contains hydrogen but no oxygen was a most important support to the hydrogen-acid theory, and completed the downfall of Lavoisier's oxygen theory;, while the isolation of cyanogen was of equal importance for the subsequent era of compound radicles in organic chemistry.
When heated with oxy-acids it dissolves, with evolution of oxygen, and with hydrochloric acid it evolves chlorine.
The oxygen and hydrogen, for example, into which water may be resolved are not in strictness indifferent one to the other, since both are members of an order regulated according to laws of combination in definite ratios.
The waste of heat in the chimney gases is accordingly greater; and further, the metallic shell is liable to be quickly burned away as a result of its contact at a high temperature with free oxygen.
Rengade (Comptes rendus, 1907, 1 44, P. 920), by partially oxidizing the metal in a current of dry oxygen and removing excess of metal by distillation in vacuo, has obtained oxides of composition Rb202 (yellowish white), Rb203 (black) and Rb204 (yellow).
The hexachloride, WC1 6, is obtained by heating the metal in a current of dry chlorine in the absence of oxygen or moisture, otherwise some oxychloride is formed; a sublimate of dark violet crystals appear at first, but as the hexachloride increases in quantity it collects as a very dark red liquid.
On the other hand the stability of the known oxygen compounds increases with the atomic weight, thus iodine pentoxide is, at ordinary temperatures, a well-defined crystalline solid, which is only decomposed on heating strongly, whilst chlorine monoxide, chlorine peroxide, and chlorine heptoxide are very unstable, even at ordinary temperatures, decomposing at the slightest shock.
Compounds of fluorine and oxygen, and of bromine and oxygen, have not yet been isolated.
Berthollet, regarding it as being a compound of hydrochloric acid and oxygen, termed it oxygenized muriatic acid.
The solution of chlorine in water, when freshly prepared, possesses a yellow colour, but on keeping becomes colourless, on account of its decomposition into hydrochloric acid and oxygen.
Davy in 1810 showed that it contained hydrogen and chlorine only, as up to that time it was considered to contain oxygen.
Chlorine and oxygen do not combine directly, but compounds can be obtained indirectly.
Balard determined the volume composition of the gas by decomposition over mercury on gentle warming, followed by the absorption of the chlorine produced with potassium hydroxide, and then measured the residual oxygen.
The solution has a pale yellow colour, and is a strong oxidizing and bleaching agent; it is readily decomposed by hydrochloric acid, with evolution of oxygen.
Further concentration leads to decomposition, with evolution of oxygen and formation of perchloric acid.
He also investigated the oxygen compounds of phosphorus and nitrogen, and was ' The names of the musical instruments in those verses of the Book of Daniel have formed the basis of a controversy as to the authenticity of the book.
By saponification it yields a number of fatty acids - palmitic, myristic, oleic, linolic, linolenic and isolinolenic. Exposed to the air in thin films, linseed oil absorbs oxygen and forms " linoxyn," a resinous semi-elastic, caoutchouclike mass, of uncertain composition.
The sulphurous acid evolved destroys such micro-organisms as may be in the cask, and in addition, as it reduces the supply of oxygen, renders the wine less prone to acidulous fermentation.
They are all decomposed on heating, with evolution of oxygen; and in contact with concentrated sulphuric acid with liberation of chlorine peroxide.
The salt finds application in the preparation of oxygen, in the manufacture of matches, for pyrotechnic purposes, and in medicine.
Given in large doses it causes rapid and characteristic poisoning, with alterations in the blood and rapid degeneration of nearly all the internal organs; but in small doses-5 to 15 grains - it partly undergoes reduction in the blood and tissues, the chloride being formed and oxygen being supplied to the body-cells in nascent form.
In that year he described a new eudiometer to the Royal Society and detailed observations he had made to determine whether or not the atmosphere is constant in composition; after testing the air on nearly 60 different days in 1781 he could find in the proportion of oxygen no difference of which he could be sure, nor could he detect any sensible variation at different places.
In another experiment he fired, by the electric spark, a mixture of hydrogen and oxygen (dephlogisticated air), and found that the resulting water contained nitric acid, which he argued must be due to the nitrogen present as an impurity in the oxygen ("phlogisticated air with which it [the dephlogisticated air] is debased").
In the 1785 paper he proved the correctness of this supposition by showing that when electric sparks are passed through common air there is a shrinkage of volume owing to the nitrogen uniting with the oxygen to form nitric acid.
William Nicholson (1753-1815) and Sir Anthony Carlisle (1768-1840) in 1800 constructed a pile of silver and zinc plates, and placing the terminal wires in water noticed the evolution from these wires of bubbles of gas, which they proved to be oxygen and hydrogen.
In the 25th series (1850) he made known his discovery of the magnetic character of oxygen gas, and the important principle that the terms paramagnetic and diamagnetic are relative.
A portion of the white metal is calcined to such a degree of oxidation that when fused with the unroasted portion, the reaction between the oxygen in the roasted matte and the sulphur in the raw VII.
Electrolytic copper should contain at least 99.92% of metallic copper, the balance consisting mainly of oxygen with not more than o oi% in all of lead, arsenic, antimony, bismuth and silver.
It rapidly absorbs oxygen, assuming a blue colour.
It turns dirty violet on exposure to air and light; in moist air it absorbs oxygen and forms an oxychloride.
Oxygen rapidly converts it into a white explosive solid.
The monoxide is formed when the metal burns in air, but is usually prepared by the ignition of the nitrate, oxygen and oxides of nitrogen being liberated.
It is a greyish coloured solid, which combines very energetically with water to form the hydroxide, much heat being evolved during the combination; on heating to redness in a current of oxygen it combines with the oxygen to form the dioxide, which at higher temperatures breaks up again into the monoxide and oxygen.
In the Brin process for the manufacture of oxygen, barium dioxide is obtained as an intermediate product by heating barium monoxide with air under pressure.
Pure antimony is quite permanent in air at ordinary temperatures, but when heated in air or oxygen it burns, forming the trioxide.
It is a pale yellow powder (of specific gravity 6.5), which on being heated strongly gives up oxygen and forms the tetroxide.
In 1785 he declared himself an adherent of the Lavoisierian school, though he did not accept Lavoisier's view of oxygen as the only and universal acidifying principle, and he took part in the reform in chemical nomenclature carried out by Lavoisier and his associates in 1787.
Oxygen and coal-gas were found to be without effect.
Anaerobic species usually require little oxygen, but aerobic species need a free supply.
Since the supply of free oxygen is dependent on the activity of green plants the process is indirectly dependent on energy derived from the sun, but it is none the less an astounding one and outside the limits of our previous generalizations.
Beyerinck and Jegunow have shown that some partially anaerobic sulphur bacteria can only exist in strata at a certain depth below the level of quiet waters where SH 2 is being set free below by the bacterial decompositions of vegetable mud and rises to meet the atmospheric oxygen coming down from above, and that this zone of physiological activity rises and falls with the variations of partial pressure of the gases due to the rate of evolution of the SH 2.
Not only so, but the evident parallelism between this absorption of light and that by the chlorophyll of green plants, is completed by the demonstration that oxygen is set free by these bacteria - i.e.
In many cases the colour-production is dependent on certain definite conditions - temperature, presence of oxygen, nature of the food-medium, &c. Ewart's important discovery that some of these lipochrome pigments occlude oxygen, while others do not, may have bearings on the facultative anaerobism of these organisms.
The conditions of phosphorescence are, the presence of free oxygen, and, generally, a relatively low temperature, together with a medium containing sodium chloride, and peptones, but little or no carbohydrates.
The idea that this film of bacteria oxidizes the alcohol beneath by merely condensing atmospheric oxygen in its interstices, after the manner of spongy platinum, has long been given up; but the explanation of the action as an incomplete combustion, depending on the peculiar respiration of these organisms - much as in the case of nitrifying and sulphur bacteria - is not clear, though the discovery that the acetic bacteria will not only oxidize alcohol to acetic acid, but further oxidize the latter to CO 2 and 01-1 2 supports the view that the alcohol is absorbed by the organism and employed as its respirable substance.
Promise of more light on these oxidation fermentations is afforded by the recent discovery that not only bacteria and fungi, but even the living cells of higher plants, contain peculiar enzymes which possess the remarkable property of " carrying " oxygen - much as it is carried in the sulphuric acid chamber - and which have therefore been termed oxydases.
Even when the light is not sufficiently intense, or the exposure is too short to kill the spores, the experiments show that attenuation of virulence, That bacterial fermentations are accompanied by the evolution of heat is an old experience; but the discovery that the " spontaneous " combustion of sterilized cotton-waste does not occur simply if moist and freely exposed to oxygen, philous bacteria.
Ciliary movements, which undoubtedly contribute in bringing the surface into contact with larger supplies of oxygen and other fluids in unity of time, are not so rapid or so extensive when compared with other standards than the apparent dimensions of the microscopic field.
The modes of cultivation described apply only to organisms which grow in presence of oxygen.
Some, however - the strictly anaerobic bacteria - grow only in the absence of oxygen; hence means must be adopted for excluding this gas.