The early history of hydroponics (nutriculture, or soilless culture of plants) is closely interwoven with that of plant physiology. In 1600, Jan Van Helmont of Belgium conducted his classical experiment, which, he claimed, proved that plants obtain all their substances from water. Van Helmont planted a 50-lb willow shoot in a tube containing 200 lbs of dried soil, which was covered to keep out dust. After 5 years of regularly adding only rainwater to the earth in the tube, the shoot increased in weight by 160 lbs. The dried soil lost less than 2 ounces in weight, a fact which Van Helmont believed to be insignificant. The plant, of course, did not live on the rainwater alone; we know today that it obtained many elements from the soil, as well as carbon dioxide and oxygen from the air.