Soon after the atomic theory was established, it was found that the plant uses as sources of food not only the air and water, but also different constituents of the soil, dissolved in the soil moisture—the mineral nutrients. Ashes of different...
The opening ceremonies of the 1904 World's Fair at the Plaza of St. Louis in St. Louis, Missouri. A crowd, seated on wide benches, faces two men at a podium at the base of the Louisiana Purchase Exposition Monument. The monument bears the words of...