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Article THE CHEMISTRY OF COMMON THINGS. Page 1 of 6 →
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The Chemistry Of Common Things.
THE CHEMISTRY OF COMMON THINGS .
BY I'lSASCIS HENRY BAKEIi . III . —AIR , AND ITS CONSTITUENTS . ' THE air of the atmosphere Avas anciently classed among the elements , and considered as a simple and undecomposable fluid . It Avas not until the latter end of the last century that its true nature
Avas known , and it Avas discovered to be composed principally of tAvo gases , each similar in their mechanical effects to air itself , but possessing very different chemical properties . These gases have been named oxygen and nitrogen , and exist in the atmosphere in the proportion of twenty-one parts of the former to seventy-nine of the latter—that is , about one fifth of the air consists of oxygenand
, four fifths of nitrogen . Oxygen is the great supporter of life and combustion , and the active principle of the air . It appears to be the most abundant body in nature , existing in a large proportion in almost every compound substance , aud constituting eight ninths of the Avei ght of water , and one third of that of the Avhole globe . It readily combines -with
all the elementary bodies , with perhaps one exception . The chemical properties of nitrogen differ considerably from those of oxygen . It neither supports life nor combustion , and a li ghted taper placed in it is immediately extinguished . It is slightly lighter than common air , and exists largely in animal matters . The proportions of oxygen and nitrogen aboA'e stated are maintained
uniformly in every situation and condition of the atmosphere . Hence these gases are usually considered as the necessary constituents of air . But besides these there are always existing Avith them two other gases , the quantities of AA'hich are variable . These are , carbonic acid gas , and vapour of Avater . The mechanical properties of atmospheric air aro similar to those
of ail other gases . It is clastic , its particles repelling each other , and consequently tho space it occupies is entirel y dependent on the pressure to which it is subject , and its temperature . Any increase of pressure Avill effect its compression , and if any part of its natural pressure be removed , an increase of its bulk will he occasioned .
Atmospheric air is , like all other material bodies , subject to the influence of gravity , as may be proved b y exhausting any vessel of the air Avhich it contains , Avhen a difference of Aveight will be found amounting to about thirty-one grains for every one hundred cubic inches . The portions of the air at the surface of the earth are maintained at their natural densit y by the wei ght of tho air above them . At a distance above the ground they are subjected to less pressure , because a less quantity of air is resting upon them , and they conse-
Note: This text has been automatically extracted via Optical Character Recognition (OCR) software.
The Chemistry Of Common Things.
THE CHEMISTRY OF COMMON THINGS .
BY I'lSASCIS HENRY BAKEIi . III . —AIR , AND ITS CONSTITUENTS . ' THE air of the atmosphere Avas anciently classed among the elements , and considered as a simple and undecomposable fluid . It Avas not until the latter end of the last century that its true nature
Avas known , and it Avas discovered to be composed principally of tAvo gases , each similar in their mechanical effects to air itself , but possessing very different chemical properties . These gases have been named oxygen and nitrogen , and exist in the atmosphere in the proportion of twenty-one parts of the former to seventy-nine of the latter—that is , about one fifth of the air consists of oxygenand
, four fifths of nitrogen . Oxygen is the great supporter of life and combustion , and the active principle of the air . It appears to be the most abundant body in nature , existing in a large proportion in almost every compound substance , aud constituting eight ninths of the Avei ght of water , and one third of that of the Avhole globe . It readily combines -with
all the elementary bodies , with perhaps one exception . The chemical properties of nitrogen differ considerably from those of oxygen . It neither supports life nor combustion , and a li ghted taper placed in it is immediately extinguished . It is slightly lighter than common air , and exists largely in animal matters . The proportions of oxygen and nitrogen aboA'e stated are maintained
uniformly in every situation and condition of the atmosphere . Hence these gases are usually considered as the necessary constituents of air . But besides these there are always existing Avith them two other gases , the quantities of AA'hich are variable . These are , carbonic acid gas , and vapour of Avater . The mechanical properties of atmospheric air aro similar to those
of ail other gases . It is clastic , its particles repelling each other , and consequently tho space it occupies is entirel y dependent on the pressure to which it is subject , and its temperature . Any increase of pressure Avill effect its compression , and if any part of its natural pressure be removed , an increase of its bulk will he occasioned .
Atmospheric air is , like all other material bodies , subject to the influence of gravity , as may be proved b y exhausting any vessel of the air Avhich it contains , Avhen a difference of Aveight will be found amounting to about thirty-one grains for every one hundred cubic inches . The portions of the air at the surface of the earth are maintained at their natural densit y by the wei ght of tho air above them . At a distance above the ground they are subjected to less pressure , because a less quantity of air is resting upon them , and they conse-