Lomonosov began his scientific career with the study of mining, but his active mind quickly led him to the considerations of physics and chemistry which occupied most of his life. Only toward the end of his career did he begin the systematic treatment of geology and metallurgy. The guiding principle of his thought in these fields became and remained a belief in the extreme age of the earth and the constant modification of its surface. He assumed the presence of a (...) central fire produced by the gradual consumption of sulphur, whose combustion produced earthquakes and mountain formation. Rock formed from clay and eroded into sand which could again be compacted to rock. Plants and animals produced alkaline and earthy materials which by combination with vitriolic acid and phlogiston from burning sulphur gave salt and metals. Fossils were petrified organic remains. (shrink)