On 17 May 1899 Joly read his paper, "An Estimate of the Geological Age of the Earth" to the Royal Dublin Society. In it, he proposed to calculate the age of the earth from the accumulation of sodium in the waters of the oceans. He calculated the rate at which the oceans should have accumulated sodium from erosion processes, and determined that the oceans were about 80 to 100 million years old. The paper was quickly published, appearing 4 months later in the Society's "Scientific Transactions". Although this method was later considered inaccurate and was consequently superseded, it radically modified the results of other methods in use at the time.