305 ON THE NATURAL HISTORY OF PYRITES AND GYPSUM. Being the Presidential Address Delivered io the Essex Field Club at the Annual Meeting on April 16th, 1904. By F. W. RUDLER, I.S.O., F.G.S., President of the Club. (With Plate XII.) THE Essex Field Club, over whose concerns it is my privilege at present to preside, is a group of some three hundred persons banded together by a common interest in the Natural History, the Geology, and the Prehistoric Archaeology of this county. It is curious to note that while the term "Natural History" stands bound, literally, to cover the history of every department of Nature, it is a term which is often used now-a-days in so narrow a sense as to suggest its limitation to living things. A "naturalist" is commonly understood to be either a zoologist or a botanist, or both, but hardly a mineralogist. Natural objects which lack the fascination of life are apt to be kept outside the pale of natural history, as though minerals were rather beneath the attention of those who are attracted by the study of plants and animals. There may be some justification for drawing a sharp line between living things and lifeless things, but surely no shadow of justification for cutting off the Mineral Kingdom from the vast Empire which is embraced by the study of Natural History. How we drifted into this practice of shutting our eyes to one- great department of natural science and narrowing the meaning of the simple expression "Natural History" in a way which even if tolerated by convenience is clearly unjustified by logic, I never could discover. The name of that man who first had the coolness to shelve one-third of Nature is not, I believe, on record. I am anxious this evening to put in a plea on behalf of Mineralogy to take its place by the side of Zoology and Botany in the grand trinity of Natural Science. It should, perhaps, be admitted at the outset that the mineralogist has himself largely to thank for the popular neglect of his science. Very little has been done, at least in this country, to place mineralogy before the public in an attractive form. So distinguished a mineralogist as Mr. L. Fletcher, the Keeper of V