26 TECHNOLOGY. 
which the spokes are secured, is of cast-iron ; the exterior is of wrought-iron 
shrunk on while hot. The wheels are all secured fast to their axles, which 
project out beyond the wheels, and run in composition-boxes which have 
their seats upon the cheeks or pendent arms, seen in jig. 1, formed of strong 
plate iron, with which the wooden frame of the locomotive is covered. 
Upon the top of each of the journal-boxes rests the end of a vertical rod, 
the other end of which is connected with the spring, which for the driving- 
wheels is placed above the main frame of the engine, and for the running- 
wheels below ; the springs are all secured to the main frame, and each bears’ 
its share of the weight of the locomotive. 
The boiler is secured to the main frame by six iron knees. P is the man- 
hole, to enable the inside of the boiler to be cleansed. o is the safety- 
valve, and upon the steam-dome there is another, immediately under the 
control of the engineer, while the other is beyond his reach. The valve 
at the back of the engine is connected with a lever secured to a 
spring balance, which serves to show at any moment the pressure of the 
steam within the boiler. Upon the top of the boiler, near to the position 
of the engineer, is the steam-whistle, for the purpose of giving signals; 
this consists of two hollow metallic half globes or balls, the upper one 
of which has a sharp edge, and is placed immediately over the lower one. 
Within the lower half globe is another slightly smaller, so arranged that 
between the two there is a narrow opening or slit all round the edge. When 
the steam is admitted from the boiler between the two cups of the lower half 
globe, it rushes out of the opening between them against the sharp edge of 
the upper cup, and the well known whistle is produced. 
Upon the end of the boiler, near the fire-door, is a glass indicator for 
showing the height of the water in the boiler. 
To soften the concussions of the cars with each other, and with the engine 
while in motion, and also as a measure of safety in case of accidents, both 
the locomotive and the passenger cars are furnished with buffers, a (pl. 5, 
jig. 19). These are cushions stuffed with horse-hair or other elastic sub- 
stance, either alone or in conjunction with steel springs. They are seen at 
the extreme forward end of the locomotive carriage in pl. 4, jig. 1. 
The locomotive is always accompanied by its tender, which carries a 
supply of fuel and water; it is seen in pl. 5; jig. 9 is a side view, jig. 10 
a longitudinal section, jg. 11 shows one half of the upper portion of the 
tender in plan. Upon the frame p, running upon four or six wheels x, 
rests a horse-shoe formed body, which serves to contain the water for the 
supply of the locomotive. This water receptacle is made of sheet-iron, and 
is entirely covered in upon top, where there are three holes closed by valves 
or covers; the centre one q receives the water, and the others communi- 
cate with spaces separated from the water-chamber, and which are used to 
carry tools and other articles which may be required during the journey. 
The vacant space left by the peculiar form of the water-box serves to carry 
the fuel. The water is fed to the locomotive through the tubes p’ and a’, 
having flexible joints to enable them to accommodate themselves, without 
breaking, to the motion of the locomotive and tender. The tender is con- 
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