CHEMICAL COMBINATION 



of all things for their intended uses than the atmosphere. 

 In it we find the source of life and health ; and chemistry 

 teaches us, most indisputably, that it is': composed of 

 certain proportions of oxygen and nitrogen gases ; and 

 experience informs us that it is on the oxygen that we are 

 dependent for all that we enjoy. So beautifully is the 

 atomic or molecular constitution ordered, that it is impos- 

 sible to produce any change in the air without rendering it 

 injurious to the vegetable and animal economy. It might 

 be thought, from the well-known exhilirating character 

 of oxygen gas, that, if a larger quantity existed in the 

 atmosphere than that which we find there, the enjoy- 

 ments of life would be of a more exciting kind ; but the 

 consequences of any increase would be exceedingly inju- 

 rious ; and, by quickening all the processes of life to an 

 unnatural extent, the animal fabric would soon decay : 

 excited into fever, it would be destroyed by its own fires. 

 Chemistry has made us acquainted with six other com- 

 pounds of oxygen and nitrogen, neither of them fitted 

 for the purposes of vitality, of which the following are 

 the most remarkable : 



Nitrous oxide, or the, so called, laughing gas, which 

 contains two volumes of nitrogen to one of oxygen, 

 would prove more destructive than even pure oxygen, 

 from the delirious intoxication which it produces. 



Nitric oxide is composed, according to Davy, of two* 

 volumes of nitrogen and two of oxygen. It is of so 

 irritating a nature, that the glottis contracts spasmo- 

 dically when any attempt is made to breathe it ; and 

 the moment it escapes into the air it combines with 

 more oxygen, and forms the deep red fumes of nitrous- 

 acid. 



Nitrous acid and the peroxide of nitrogen each con- 

 tains an additional proportion of oxygen, and they are 

 still more destructive to all organization. 



Nitric acid contains five volumes of oxygen united to 

 two of nitrogen ; and the well-known destructive pro- 

 perties of aqua fortis it is unnecessary to describe. 



