Raspail, Scientist and Reformer

soil in which they were found but are the remains of animals living in the sea on whose bed the soil (sediment) was deposited. The latter paper is a summary of a projected further work which unfortunately never appeared. It is the Prodromus that contained the first statement of the Law of Superposition; and much more. 'If, in a certain stratum, we find great abundance of rushes, grass, pine cones, trunks and tree branches and similar objects, we surmise correctly that the said material was swept thither by a river in flood or by a torrential outbreak.' Here is a clear statement that the contained fossils indicate the environment in which the rock was formed. Steno gives criteria for recognizing fresh water, marine and volcanic deposits. He also recognized that sediments were originally deposited in a horizontal position, that some have subsequently been tilted, and that they were laid down either universally or in confined basins '.. . Wherever bared edges of strata are seen, either a continuation of the same strata must be looked for or another solid substance must be found that kept the material of the strata from being dispersed.' In mineralogy we owe to Steno the first recognition of the law of constancy of interfacial angles, a law which waited until 1783 for its first experimental proof. Steno, too, was probably the first to observe and record the striations on the faces of pyrite cubes. In structural geology he classifies mountains and draws sketches of and summarizes the geological history of Tuscany. Steno was already a Catholic when the Prodromus appeared: he was accepted into the Roman Catholic Church in 1667. Accepting the Usher Chronology for the origin of the earth he strives to show that his observations were not incompatible with the Scriptures and that the remains of elephants found in the Arno Valley are the remnants of Hannibal's army. Unfortunately hejust failed to erect a geological chronology. For the geologist, and for science in general the most unhappy date in Steno's life must be 1675 when he was ordained a priest in Florence. From that time Steno's interests turned from science to theology; without doubt geology's loss was greater than the Church's gain. An English translation of the Prodromus by J. G. Winter appeared in 1916 and has lately been reprinted (1968). The value of the present work is that it brings together the …