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[Page 82]
Oifebruithc
According to the foregoing Calculation Mr. Ericksons must work at an effective Pressure of [illegible] Pounds per square Inch on the Steam Piston; let us see what Mr. Stephensons Rocket Engine would be at the same Pressure.
In fol. the Area of the Steam Piston is [illegible] sqr. Inches then rc.or x hr = isrt.sr Pounds effective Pressure on the Steam Piston; and as the Velocity of the Steam Piston is[illegible] feet per minute.
[illegible] Horse Power for one Cylinder and
[Page 83]
[illegible] HorsePowers say [illegible] Horse Power of the Engine at [illegible] Miles per Hour.
The last Engine Mr. Stephenson tried was Called the Wildfire and this had [illegible] Copper tubes each 0 Inches in diameter in the Boiler the Cylinders were [illegible] Inches in diamr. and were laid exactly horizontal. in all other respects the Engine was the same as the Rocket.
Now presuming that Mr. Stephenson had made the Boiler of sufficient Power to maintain the Steam in the Boiler at [illegible] Pounds per square Inch and to supply the Cylinders with the full quantity of steam when the
