Before the time of Clair Patterson, many people from philosophers to scientists had been trying to determine the age of the Earth. Aristotle believed that the Earth always existed and always will exist. In 1510, Leonardo Da Vinci pondered fossil sea shells and concluded that they could not have been laid down by the Noachian flood spoken of in the Bible. In 1654, Archbishop James Ussher estimated, in the context of the bible, that the Earth was created in 4004 BC. Decades of observation and thinking passed, and more scientists began to try to figure out the age of the Earth. In the 1660s, Nicolaus Steno became the first to state rules that connected information derived from fossil remains and strata, allowing him to concisely state the ideas of the law of superposition and the principle of original horizontality. These new principles lead to the thought that fossils could be used to chronologically order layers of rock.
In 1779, Comte de Buffon performed an experiment to determine the age of the Earth. His experiment involved melting rocks and then timing how long the rocks took to cool and solidify. He then applied the information he found to the whole Earth, and estimated its age to be around 75,000 years old. In 1788, James Hutton claimed that the Earth went through a series of cyclic depositions and uplifts and so had no beginning or end; thus, it was infinitely old. Hutton also came up with the idea that present is the key to the past, meaning that geologic manifestations present today can tell scientists about how they were formed in the past. This idea became known as uniformitarianism; the thought that all geologic processes occur at the same rates and the same processes will always yield the same outcomes. In 1862, William Thompson estimated the Earth to be from 20-40 million years old. Both Charles Lyell and Charles Darwin believed all of these ages to be too short. Other estimates in the late 1800s made by scientists such as Hermann von Helmholtz in 1856, Simon Newcomb in 1892, John Perry in 1895, John Joly in 1900 and George H. Darwin calculated the age of the Earth to be 22, 18, 20-400, 80-100, and 56 million years, respectively. Some of these calculations analyzed tidal friction, accumulation of salt from erosion, and variations in animal species to determine the age of the Earth. These estimates were all too short, as none of these people had taken into account radioactive decay and mantle convection within the Earth, because they had not yet been discovered.
A more accurate measurement of the Earth’s age was made in 1946 when a geologist named Arthur Holmes used radiometric dating to determine an age for Earth rocks. He worked at Durham University and was incredibly underfunded, to the point where he had to wait for a full year for the university to supply him with an adding machine. Holmes’ method was to measure the decay rate of uranium into lead to calculate the age of rocks and then hopefully the Earth. Some difficulties came along with his method. First, he had not been provided with proper equipment to take measurements of small samples. Second, it would have been difficult for him to measure the exact age of the Earth. The proper way to determine the age of the Earth would have been to obtain incredibly old rocks or minerals and determine their ages. Last of all, his fellow scientists did not believe his findings. While he did find the Earth to be at least three billion years old, and his peers praised his methodology, they believed he had only found the age of materials from which the Earth had formed.