28 THE REASOK WHY. 



"fiive instruction to a wise man, and he will be yet wiser ; teach a just 01*4. 

 and he will increase in learning." PKOVEBBS IX. 



precious metals from what at first appeared to be useless stones 5 

 transparent glass from pebbles, through which no light could pass ; 

 soap from oily substances ; and gas from solid bodies. 



Knowledge of Medicine enables the physician to overcome the 

 ravages of disease, and to save suffering patients from sinking 

 prematurely to the grave. 



Knowledge of Anatomy and of Surgery enables the surgeon to 

 bind up dangerous fractures and wounds, and to remove, even from 

 the internal parts of bodies, ulcers and diseased formations that 

 would otherwise be fatal to life. 



Knowledge of Mechanics enables man to increase his power by 

 the construction of machines. The steam-ship crossing the ocean 

 in opposition to wind and tide, the railway locomotive travelling at 

 60 miles an hour, and the steam-hammer beating blocks of iron into 

 useful shapes, are evidences of the power which man acquires through 

 a knowledge of mechanics. 



Knowledge of Electricity enables man to stand in comparative 

 ;y amid the awful war of the elements. Lightning, the offspring 



electricity, has a tendency to strike upon lofty objects by which 

 it may be attracted. By its mighty powers churches or houses 

 may be instantly levelled with the dust. Bijt man, knowing that 

 electricity is strongly attracted by particular substances, raises over 

 lofty buildings rods of steel communicating with bars that descend 

 into the ground. The lightning, rushing with indescribable force 

 toward the steeple, is attracted by the bar of steel, and conducted 

 harmlessly to the earth. Man may thus be said to take even light- 

 ning by the hand, and to divert its destroying force by the aid of 

 Knowledge. And in countless other instances " Knowledge is 

 Power." 



CHAPTER II. 



4. Why do we breathe air? 



Because the air contains oxygen, which is necessary to life. 



5. Why is oxygen necessary to life ? 



Because it combines with the carbon of the blood, and fara* 

 carbonic acid gas. 



