Page:Historic highways of America (Volume 15).djvu/148

 and has sharper angles than that broken by machinery, but the latter, when properly assorted or screened, has been found to meet every requirement.

"A good crusher driven by eight horsepower will turn out from forty to eighty cubic yards of two-inch stone per day of ten hours, and will cost from four hundred dollars upward, according to quality.

"Some crushers are made either stationary, semistationary, or portable, according to the needs of the purchaser, and for country-road work it is sometimes very desirable to have a portable crusher to facilitate its easy transfer from one part of the township to another. The same portable engine that is used in thrashing, sawing wood, and other operations requiring the use of steam power may be used in running a stone crusher, but it is best to remember that a crusher will do its best and most economical work when run by a machine having a horsepower somewhat in excess of the power actually required.

"As the stone comes from the breaker the pieces will be found to show a considerable variety in size, and by many practi-