The foregoing remarks indicate in a general way the significance of the weather map and the principles upon which scientific weather predictions are based. The endless procession of highs and lows brings to any place on the map constant alternations of heat and cold, storm and sunshine. The forecaster watches the procession, and draws his inferences as to what will happen in this or that part of the country within the next day or two (forty-eight hours is about the limit of his outlook). "Long-range" forecasting is still a thing of the remote future. Forecasts for a week in advance, are, indeed made by the Weather Bureau with the aid of reports from a chain of stations extending round the globe, but these are in very general terms. [Illustration: MARVIN RAIN AND SNOW GAGE With trumpet-shaped wind-shield at top. In the middle is seen the cylindrical collector. This is removed and weighed with its contents to ascertain the amount of rain or snow that has fallen] In January, 1914, the Bureau began publishing a "daily weather map of the Northern Hemisphere." This publication is, at present, suspended on account of the war. SOME WEATHER MISCELLANIES It would require a book, rather than a brief essay, to describe all the vicissitudes of weather, and many books that attempt to do this have been written.[A] We have space here only to mention a few important features of the weather met with in our own country. [A] See "Brief List of Meteorological Textbooks and Reference Books," 3d ed., by C. Fitzhugh Talman. For sale by the Superintendent of Documents, Washington, D. C. Price 5 cents. The southern and southeastern part of a cyclone, some hundreds of miles from the center, is a favorite breeding-ground for _thunderstorms_ and _tornadoes_. Thunderstorms of the type known as "heat thunderstorms" also occur with no special relation to cyclonic centers in regions where the ground has been intensely heated. In either case the storm is built up by rapidly ascending air, which cools and condenses its water vapor, first into enormous clouds (_cumulo-nimbus_, or "_thunderheads_"), and then into rain, frequently accompanied by hail. It would be necessary to go to some length to explain the familiar electrical manifestations of the thunderstorm--some points, indeed, are not perfectly clear to meteorologists--but it should be stated that these are always the result, not the cause, of the storm. _Lightning_ is an electrical discharge between cloud and earth, or cloud and cloud, and _thunder_ is simply the violent soundwave set up by the sudden expansion of the heated air along the path of the discharge,--the same acoustic phenomenon that accompanies an ordinary explosion. [Illustration: THE EFFECTS OF AN ICE STORM AT CANTON, N. Y. March 25-27, 1913] [Illustration: SUMMIT HOTEL AT SUMMIT, CAL.