76 GASEOUS MINERALS 



CLASS I.— GASES 



The gases occurring native are as follows : 1. containing 

 &r consisting of nitrogen : atmospheric air, nitrogen. 2. 

 containing hydrogen : carbureted hydrogen, phosphureted 

 hydrogen, sulphureted hydrogen, muriatic acid. 3. contain- 

 ing carbon or sulphur : carbonic acid, sulphurous acid. 



ATMOSPHERIC AIR 



1. Atmospheric air is the air we breathe It consists of 

 oxygen 21 per cent, by weight, and nitrogeu 79 per cent., 

 with a small proportion of carbonic acid. It has neither color 

 odor, nor taste., It supports life and combustion through the 

 oxygen which it contains, this gas being used or absorbed 

 in respiration as well as in the burning of wood or a candle. 

 The oxygen thus consumed is restored to the air again by 

 vegetation which gives out oxygen through the day, and in 

 this way the quality of the atmosphere requisite for life is 

 sustained. It is about 815 times lighter than water, and 

 1 1,065 tim?3 lighter than mercury. A hundred cubic inches 

 weigh abc&t 31 grains. 



NITROGEN GAS. 



Nitrogen destroys life, and has neither color, odor nor 

 taste. It is one of the constituents of -the atmosphere. It 

 bubbles up through the waters of many springs, having been 

 derived from air by some decompositions in progress within 

 the earth, by which the oxygen of the air is absorbed. 



Lebanon springs in Columbia county, New York, and a 

 region in the town of Hoosic, Rensselaer county, afford 

 large quantities of this gas. There is another locality at 

 Canoga, Seneca county, where the water is in violent ebul- 

 lition from the escape of the gas ; its temperature is 40° F. 

 There are other nitrogen springs in Virginia, west of the 

 Blue Ridge at Warm and Hot Springs ; in Buncombe 

 county, N. C. ; and on the Washita in Arkansas. At Bath, in 

 England, nitrogen is escaping from the tepid springs at the 



What gases occur in nature ? What is the constitution of the at- 

 mosphere] its general characters? the weight? What is said of the 

 characters of nitrogen? Where does nitrogen occur in nature ? 



