Scale 20
Friction Diagram from Allen Engine at Fair of American Institute, 1870.
Scale 24
Gage Pressure 60
Diagram from Allen Engine, Fair of American Institute, 1870, cutting off at ¹⁄₄ stroke.
From this I concluded that in these engines the use of the friction brake is unnecessary; the friction is sensibly the same under all loads, and the friction diagram only needs to be subtracted to learn from the diagram the amount of effective work done.
The verdict of the judges, President Barnard of Columbia College, Thomas J. Sloane, the proposer of the gimlet-pointed wood screw, now in universal use, in place of the flat-ended screws formerly used, and inventor of the special machinery required for their manufacture, and Robert Weir, engineer in the Croton Aqueduct department, may be summed up in the single expression from their report, “The performance of this engine is without precedent.” For its success I was largely indebted, first, to the remarkable circulation and steam-generating power of the boiler, and, second, to the superheating of the steam in the second drum.
CHAPTER XVIII
Demonstration to the Judges of Action of Reciprocating Parts. Explanation of this Action. Mr. Williams’ Instrument for Exhibiting this Action.
