shall need two cords and a half. Look into the tank; you see it is full of 

 water; but we shall have to take some more; for between here and Colum- 

 bus, 1 558 gallons of water must be flashed into steam, and sent traveling 

 through the cylinders. 



But we are off; you see this hill is before us; and looking behind, you will 

 see that another engine is helping us. Notwithstanding that help, let us 

 see what the Deshler is doing, and how Johnny manages her. She is carry- 

 ing a head of steam which exerts on every square inch of the internal surface 

 of the boiler, a pressure of 1 20 pounds. Take a glance at the size of the 

 boiler; it is 17 feet 6 inches long, and 40 inches in diameter. Inside of it 

 there is the fire-box, 48 inches long, 62 inches deep, and 36 across. From 

 this to the front of the engine, you see a lot of flues running. There are 1 1 2 

 of these, 10 feet 6 inches long, and two inches in diameter; and of the inner 

 surface of all this, every square inch is subjected to the aforesaid pressure, 

 which amounts to a pressure of 95,005 pounds on each flue. Don't you 

 think, if there is a weak place anywhere in this boiler, it will be mighty apt 

 to give out? And if it does, and this enormous power is let loose at once, 

 where will you and I go to? Don't be afraid, though; for this boiler is built 

 strongly; every plate is right and sound. Open that fire-door. Do you 

 hear that enormously loud cough? That is the noise made by the escape, 

 through an opening of 3 1 square inches only, of the steam \vhich has been 

 at work in the cylinder. You can feel how it shakes the whole engine. 

 And see how it stirs up the fire. Whew! isn't that rather a hot-looking 

 hole? The heat there is about 2800° Centigrade scale. [*] But we begin to go 

 faster. Listen! try if you can count the sounds made by the escaping 

 steam, which we call the "exhaust." No, you cannot; but at every one of 

 those sounds, two solid feet of steam has been taken from the boilers, used 

 in the cylinder, where it exerted on the piston, which is fourteen inches in 

 diameter, a pressure of nine tons, and then let out into the air, making, in 

 so doing, that noise. There are four of those '"exhausts" to every revolu- 

 tion of the driving-wheels, during which revolution we advance only 17% 

 feet. Now we are up to our speed, making 208 revolutions, changing 33}^ 

 gallons of water into steam every minute we run, and burning eight solid 

 feet of wood. 



We are now running a mile in one minute and twenty-six seconds; the 

 driving-wheels are revolving a little more than 3)2 times in each second; 

 and steam is admitted into, and escapes from, the cylinders fifteen times 

 in a second, exerting each time a force of nearly nine tons on the pistons. 

 We advance 61 feet per second. Our engine weighs 22 tons; our tender 

 about 17 tons; and each car in the train with passengers, about 17 tons; 



*This temperature was apparently in error for iron melts at 1535° C 



132 



