What Does Horse Power Mean?

The term “horse power” is used in describing the amount of power produced by an engine or motor. When man made the first engines he needed some term to use in describing the amount of power his engine could develop. Up to that time man had used the horse for turning the wheels of his machinery and the horse to him naturally represented the most powerful animal working for man. When engines came into use they replaced the horses because they were capable of developing many times the power of the horse. In finding an expression which would accurately convey to the mind of another the power of a particular engine, it was natural to say that this engine would do the work of five, ten or more horses, and as this described it accurately and in a way that was entirely clear, it became customary to describe the power of an engine as so many times the power of one horse.

To-day we still cling to the term “horse power” in describing the strength of the engine, although the horse-power unit used to-day is greater than the power of an average horse. To speak of an engine of one horse power to-day means an engine that has the power to lift 30,000 pounds one foot in one minute.

WHERE OUR COAL COMES FROM

A COAL BREAKER.

Coal is brought in mine cars from several mine shafts and slopes, dumped onto a conveyor that runs on the inclined framework shown at the right of the picture. At the top it is broken in rolls, sorted and sized as it slides through the different screens, pickers, etc., and is finally delivered into railroad cars.