No clear-cut distinction can be drawn between professionals and amateurs in science： exceptions can be found to any rule．Nevertheless，the word“amateur”does carry a connotation that the person concerned is not fully integrated into the scientific community and， in particular，may not fully share its values．The growth of specialization in the nineteenth century，with its consequent requirement of a longer，more complex training，implied greater problems for amateur participation in science．The trend was naturally most obvious in those areas of science based especially on a mathematical or laboratory training，and can be illustrated in terms of the development of geology in the United Kingdom．