Most unfairly was Hutton attacked, and he was thus defended by his friend Playfair: “In the planetary motions, where geometry has carried the eye so far, both into the future and the past, we discover no mark either of the commencement or termination of the present order. It is unreasonable, indeed, to suppose that such marks should anywhere exist. The Author of nature has not given laws to the universe, which, like the constitutions of men, carry in themselves the elements of their own destruction. He has not permitted in his works any symptom of infancy or of old age, or any sign by which we may estimate either their future or their past duration. He may put an end, as He no doubt gave a beginning, to the present system at some determinate period of time; but we may rest assured that this great catastrophe will not be brought about by the laws now existing, and that it will not be indicated by anything which we perceive.” Hutton studied meteorology, and gave to the world the first reasonable theory of the cause of rain. He described the formation of invisible vapour by evaporation, the production of visible mist and cloud, and finally rain. And he investigated the reasons of the cause of rainfalls differing in amount in the tropics and temperate zones of the earth. In 1793 serious illness attacked Hutton after he had been writing his speculations regarding matter. On his recovery he republished his work on the “Theory of the Earth,” and replied to many of the attacks upon it, and later on wrote a work which was not published in the “Elements of Agriculture.” Illness again seized him, and he died in 1797.