The cause of the ice ages was a puzzle to nineteenth-century climatologists. One of the most popular theories was that the affected continents must somehow have been hugely elevated and, like mountains, iced over. However, in this 1885 study of the problem, James Croll (1821 90) argues that such staggering movement would have been impossible. Instead, he puts forward a new theory: that the eccentricity of the earth's orbit changes at regular intervals over long periods, creating 'great secular summers and winters'. Adopting a meticulous approach to the facts, he disproves a host of well-established notions across several disciplines and makes some remarkable deductions, including the effect of ocean currents on climate, the temperature of space, and even the age of the sun. With a focus on logical argument and explanation rather than mathematics, his book remains fascinating and accessible to students in the history of science.

James Croll (1821-90) was self-educated, but on gaining a post at the Glagow Andersonian Museum had the time to explore his academic interests. Despite his lack of formal training, he quickly became a leading light of the Scottish Royal Geological Society. Using physics, mathematics, geology and geography he explored the pressing scientific questions of the time. In this, his final book, published in 1889, Croll divides his focus between 'the probable origin of meteorites, comets and nebulae', the age of the sun and the impact of the pre-nebular condition of the universe on star evolution. Using both proven facts and theories, Croll explores the ideas and hypotheses then current, frequently crediting colleagues for their work, and building on it. Croll, who from humble beginnings became a Fellow of The Royal Society and of St Andrew's University, writes in a style which makes his works accessible to a lay readership.

This first book by James Croll (1821 90), published in 1875, includes many of the original geophysical theories that he had formulated throughout the early years of his career. A self-educated amateur, Croll obtained work at the Glasgow Andersonian Museum, which gave him leisure time to pursue his scientific interests. The fluidity of scientific disciplines at the time allowed him to virtually invent the field of geophysics, and his unique insights united ideas previously thought unconnected, such as using physics to explore the causes of the glacial epochs, climatic changes and the circulation and temperature of ocean currents. Croll, whose Stellar Evolution and Its Relations to Geological Time is also reissued in this series, later became a Fellow of the Royal Society and of St Andrew's University, but (possibly because of his non-scientific background) he writes in a style which makes his works accessible to a lay readership.