The meteorological services of all civilized countries adjacent to the sea display signals along their coasts to announce the coming of storms dangerous to navigation. One of the earliest devices used for this purpose was the “aeroclinoscope,” a form of semaphore formerly employed by the meteorological service of Holland. The position of the arm of the semaphore indicated the region in which the barometer was low; i. e., the storm center. In the British Isles, in the middle of the last century, Admiral FitzRoy introduced the use of canvas cones and “drums” (i. e., cylinders), which, seen from any direction, have the appearance of solid triangles and squares against the background of the sky. The British later abandoned the drum and used the cone only, pointing up or down for northerly or southerly gales, respectively. The American storm flag--red with a square, black center--was adopted by the United States Signal Service (the predecessor of the Weather Bureau) in 1871. This signal was subsequently amplified by the addition of red and white pennants to show the expected direction of the wind at the beginning of the approaching storm. Most countries use lanterns for night storm signals. In the year 1909 a uniform system of signals, consisting of cones by day and lanterns by night, was recommended for use in all countries by an international commission which met in London. In spite of this recommendation some thirty or forty different systems of daytime storm signals are now in use in different parts of the world. On the China coast an elaborate system of signals, consisting of cones, balls, diamonds, and squares displayed on a mast and yardarms, indicates the existence of a typhoon anywhere in the neighboring seas, together with its location and movement. CHAPTER XVIII AERONAUTICAL METEOROLOGY During the great war the British Government decided, in its wisdom, to establish a flying field in Scotland, at which aviators were to be trained in dropping bombs. The commission having this matter in hand chose a site on the shores of Loch Doon. In laying out the field a bog had to be drained; then a railway was constructed, hangars were erected, and other operations were carried out, entailing altogether an expenditure of half a million pounds. At a certain late stage in the proceedings the disconcerting discovery was made that the field could never be successfully used for the purpose intended, on account of the gusts and eddies produced by the surrounding hills. The undertaking was therefore abandoned. The authorities had presumably enlisted the skill of engineers from the outset of the work--but they had failed to consult a meteorologist!