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out of the whole year their performance was only^tlisof what it was the remaining seven months.Adopting this to the loco-motive engine,
We have as 4 13;; 975 : 73 lj, the minimum perform-ance in -j^ths of the time, and 975 the maximum -j^ths, theaverage would make 874 cwt. or 43 tons 14 cwt.
To procure even numbers, I shall say 40tons, moved at the rate of 6 miles an hour upona horizontal Edge-rail-road.
Taking this as a standard of the per-formance of a loco-motive engine upon alevel Edge-rail-road, the following Table willshew its relative effect with horses.