[Sidenote: Towers.] “The towers on the north of the building have each a central smoke-shaft from the heating apparatus, the boilers of which are placed in the basement, immediately between the towers, while the space surrounding the smoke-shafts is used for drawing off the vitiated air from the various galleries contiguous thereto. The front galleries are ventilated into the front towers, which form the crowning feature of the main front. These towers also contain, above the second floor, various rooms for the work of the different departments, and on the topmost storey large cisterns for the purpose of always having at hand a considerable storage of water in case of fire. On the western side of the building, where it is intended that the Zoological collection shall be placed, the ornamentation of the terra-cotta (which will be found very varied both within and without the building) has been based exclusively on living organisms. On the east side, where Geology and Palæontology find a home, the terra-cotta ornamentation has been derived from extinct specimens. “The Museum is the largest, if not, indeed, the only, modern building in which terra-cotta has been exclusively used for external façades and interior wall-surfaces, including all the varied decoration which this involves.” * * * * * [Sidenote: Gardens.] The gardens on the south, east, and west sides of the Museum are open to the public whenever the Museum itself is open, under certain regulations, posted at the entrance gates. GENERAL ARRANGEMENT. [Sidenote: Use of the term Natural History.] Natural History is an old term, used to describe the study of all the processes or laws of the Universe, and the results of the action of those processes or laws upon such of its constituent materials _as are independent of the agency of man_. It is thus contrasted with the history of Man and his works, and the changes which have been wrought in the World by Man’s intervention. This distinction afforded a convenient and rational basis for the division of the numerous and multifarious objects which had been collected together in the British Museum at Bloomsbury. When it was decided to effect a separation of the collections, those that were purely the products of what are commonly called “natural” forces were removed to South Kensington, while those showing the effects of Man’s handiwork remained at Bloomsbury. Like most others of the kind, this distinction cannot be applied very rigidly. Such lines of demarcation almost always overlap. For instance, examples of modification of animal or plant structure under Man’s influence legitimately find a place in a Museum of Natural History, especially as they may afford illustrations of the mode of working of natural laws. Prehistoric stone-implements, again, are shown in the Geological Department, in order to illustrate the co-existence of Man with extinct Mammals.