Originally, exactly as much as a volume of water equal to the cube of the hundredth part of the metre, at the temperature of melting ice. I don't find that terribly helpful. Not many did. That's why, in 1889, the mass of the kilogram was redefined as being equal to the IPK.
Boiling water is also an effective poison ivy killer. If the area where you will be killing poison ivy has no other plants you wish to keep, pour boiling water over the poison ivy plant. Boiling water will kill any part of a plant that it comes in contact with, so be careful using this around desirable plants.
Poison ivy, poison oak, and poison sumac grow in wooded or marshy areas throughout North America. The plants arenât really poisonous. They have a sticky, long-lasting oil called urushiol that causes an itchy, blistering rash after it touches your skin. Even slight contact, like brushing up against the leaves, can leave the oil behind. Poison ivy and poison oak grow as vines or shrubs. Poison sumac is a shrub or tree.