In dealing with a mountain group, therefore, the traveller should note where he can get the information as to the past, the date of the commencement of the actual movement of _each glacier_, and in all cases whether the ice is in advance, or retreat, or stationary. Of course the rate of forward movement, or velocity of the ice, and the oscillations in the extension of the ice must be kept carefully distinct. Observations should also be made on the presence of blue bands, and their relation to the lines of stratification in the névé noted. Should time and circumstances permit, a series of observations of the velocity of the ice is of value. These may be made after Tyndall’s method, by planting a line of sticks across the glacier, or by painting marks on boulders, the position of which relatively to ascertained points on the mountain-side has been accurately fixed. The size of the glacier that is, the area of its basin and its length, also the slope of its bed above, as well as at the point measured, should be noted. The rate of movement of the ice appears to be connected both with the volume of the glacier and the inclination of its bed, and is considerably affected by temperature. Thus a rise in temperature may even be accompanied by a temporary advance, but in this case a sagging will take place higher in the névé, producing a concave cross-section, showing that the advance is not due to increased snowfall, but to a decrease in the viscosity of the ice. The advance or retreat of a glacier are not the only factors to take into account in estimating the decrease or diminution of the volume of ice. The highest level of the transverse convexity of the glacier at various points in its course should also be noted. If the glacier is bounded laterally by rocky walls, marks may conveniently be painted on these, opposite one another. The vertical height of the marks above the ice at the sides should be noted, and the date of the observation recorded. A society, entitled the Commission Internationale des Glaciers, has been formed to promote the study of glacial movements and other points of interest and importance. Their reports from their inception to 1905 were published in the ‘Archives des Sciences,’ Geneva, the journal of the Swiss Alpine Club, and from 1906 to 1913 in the ‘Zeitschrift für Gletscherkunde,’ Berlin. A summary of the reports in English appeared throughout these years in the ‘Journal of Geology,’ Washington. The European War has disorganised this international society, but steps are being taken to establish some organisation to replace it. IV. NATURAL HISTORY.[7] _By the late H. W. BATES, F.R.S._ Revised by W. R. OGILVIE-GRANT, _British Museum (Natural History)_.