part by weight

In its sixth report the Royal Commission recommended that the standard set should be 15 parts by weight per million of water.

Roux is made of equal parts by weight of flour and butter cooked.

Spirit Splash was made possible in part by weight testing performed on the Reflection Pond in preparation for President Richard Nixon's visit to the university to speak at its 1973 commencement.

Under average conditions, 100 parts of wood yield about 60 parts by volume, or 25 parts by weight, of charcoal; small-scale production on the spot often yields only about 50%, large-scale was efficient to about 90% even by the seventeenth century.

The formula for black powder remains today what it was hundreds of years ago - 75 parts by weight of potassium nitrate, 15 parts of charcoal and 10 parts of sulfur - but the fireworks in which it is used have changed radically.