PRESIDENTIAL ADDRESSES. 35 



While oxygen is one of the chief components of all vegetable and 

 animal substances, and its work in the animal kingdom is absorbingly 

 interesting, I wish at this time to attract your attention more particu- 

 larly to its special importance in the mineral kingdom. However, it 

 would be well to bear in mind that everything on the earth, and of 

 the earth, and about the earth, is mineral. The air we breathe, the 

 food we eat, the clothes we wear, every article in use by man, our 

 bodies, every living and inanimate thing, are made up of mineral ele- 

 ments and are resolvable into mineral elements. 



We might justly call oxygen the Ariel among the elements, mar- 

 shaling its fairy hosts at will in every conceivable parade of beauti- 

 ful crystalline forms and colors. Its combinations with the metals 

 gives the coloring matter that tints all the beautiful varieties of min- 

 erals, as well as all the brilliant and varied colors of the flowers and 

 the vegetable kingdom. 



Its combinations with silicon, calcium and potassium make it practi- 

 cally the most important constituent of all rocks. The primal granites, 

 all the igneous and metaraorphib rocks, all of the felsites, quartzites, 

 the sandstones, the shales and limestones, owe their hardness, their 

 durability and their existence to this fairy, airy element, light and 

 colorless as the air. 



Nearly all the beautiful crystallizations of every variety of form 

 and color that make up the gems of the earth are the affectionate and 

 obedient subjects of this master element. With varying proportions 

 of silicon and other elements it makes the harcl, durable granites, 

 quartzites, diorites, trachytes, rhyolites, as well as the sandstones and 

 softer shales. Associated with carbon it unites with calcium, and 

 makes the limestones in all their variety, from the coarse, argillaceous, 

 magnesian limes to the perfectly crystallized white and colored mar- 

 bles and the brilliant, transparent calcites. 



One of the most remarkable illustrations of its fancy is exhibited 

 in its union with the soft, white element aluminum, making alumina, 

 more commonly known as corundum, or emery, the mineral next in 

 hardness to the diamond; and when it is found pure and transparent 

 it makes the most valuable and most beautiful gems of the earth — 

 the ruby, the sapphire, and the emerald. These gems, when pure, are 

 simple oxides of aluminum, colored with the presence of a metallic 

 oxide so small in quantity that the skill of the chemist cannot 

 measure it. 



Oxygen is the life-giving and sustaining element ; the active princi- 

 ple of combustion ; the heart of fire. Life cannot exist in the animal 

 kingdom but a few moments without it. 



While it is the life builder and the life-sustaining force in nature, 

 yet, strange contrariety, immediately upon the cessation of life its 



