8 THE AIR AND THE GASES IN IT. 



are formed by oxygen uniting with other metals. These 

 compounds are called oxides. 



23. Oxygen was called a producer of acids, because it 

 is an element of many of the most powerful acids ; and 

 the name acid is given to several substances which are 

 extremely sour and very corrosive, and produce the effect 

 of turning vegetable blue colors red. 



24. Oxygen, for instance, unites with sulphur, or brim 

 stone, in two proportions. If there be sixteen parts by 

 weight of sulphur to sixteen of oxygen, sulphurous acid 

 is formed ; sixteen of sulphur to twenty-four of oxygen 

 form sulphuric acid, commonly called oil of vitriol, a 

 heavy liquid, looking like oil. 



25. Eight parts out of nine in the composition of water 

 are oxygen ; the other part is hydrogen. 



26. Hydrogen (water producer) is an invisible air or 

 gas, elastic, and without color, taste, or smell, and lighter 

 than any other substance known. One hundred cubic 

 inches of hydrogen weigh 2 T ^ grains. 



27. Oxygen, which is a little heavier than common air, 

 is sixteen times heavier than hydrogen. 



28. And common air is about 816 times lighter than 

 pure water. 



29. Nitrogen is a gas which alone does not sustain 

 combustion, nor the breathing or respiration of animals. 

 A burning candle placed in a vessel full of it goes imme 

 diately out. An animal placed in it immediately dies. 

 It is not supposed to be poisonous, but merely inert. It 

 serves to temper the violent action of oxygen, which, 

 without it, might consume the lungs which should breathe 

 it. It enters as an essential element into the structure 

 of animals and plants. It has neither color, taste, nor 

 smell. 



