RULES FOR CALCULATING THE STEAM ENGINE.

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Example ,—To find the diameter for the steam-pipe of an engine, of which the diameterof the cylinder is 2 feet, the length of stroke 2 - 5 feet, and the number of strokesPer minute 38.

Length of stroke 2'5

Number per minute 38

200

75

Divide by 6) 95'0

16, nearly

Square root 4

Diameter cylinder 24 inches

Divide by 20) 96

4’8 inches.

The diameter of the pipe should therefore be about 5 inches.

The same rule applies to the steam passages and the passages to the condenser.

• FIRE GRATING.

9- To find the area of the grating.

Rule. —Divide twice the square root of the height, in feet, from the bottom of theas h-pit to the bottom of the chimney by the said height, and multiply the quotient bythe number of horse-power. The result will be the area of the grating expressed insquare f ee t. ( 107 .)

Example. —Let the height be 5 feet, and the number of horses’ power 96.

Square root of 5 = 2 - 282

Divide by 5) 4'560-91

Horse-power 96

546

819

87 - 36 square feet for the grating.

CHIMNEY .

To fi n d the area of a chimney for a steam engine.

squa L - E '—Tor engines of 10 horse-power and upwards the area of the chimney, in

h • , lnc hes, should be 112 times the horse-power divided by the square root of its] ght. (i 49 n

D