marks: "There is a crying need for a weather map of the whole northern hemisphere, if not for the world. A world meteorological foundation has been proposed. It has been stated that to gain the participation of America, some problem having a bearing upon American meteorology should be undertaken. What better problem could be undertaken than to secure sufficient data to make an excellent and complete daily weather map for the whole world and to make possible its speedy publication." Prof. R. DeC. Ward, professor of climatology in Harvard University, said in a recent paper: "If we knew the variations in solar activity in advance, and if in addition the direct and indirect effects of such variations upon the earth's atmosphere were understood, then regular longrange forecasts would be possible." Before we reach that stage, however, Professor Ward says, "we must have a great many more solar observations and also a very exhaustive study of the meteorological data for many years and for hundreds of stations all over the world." Here again the world weather map is called for. The problem of how to establish and maintain a world weather map is an international problem-of the gentler sort and it will require much time and effort on the part of dreamers to overcome the natural difficulties of getting the whole world to co-operate. The matter of securing daily observations and reports of such character as to make it possible to produce an accurate, satisfactory world weather map at one or more centers will involve large expenses and much technical labor. But what could be more universally interesting-yea, valuable, commercially—than a daily chart showing the condition and activities of the atmosphere of the entire globe? It would be somewhat like capturing the most vast and elusive entity known to man and isolating it in a laboratory, and viewing and studying it as a unit. Really, we can conceive of no undertaking in which the peoples of all nations could unite so freely and unselfishly. The atmosphere is the one thing we have that is absolutely a world affair, in which no person or set of people has superior claims. It is the one thing that all mankind possesses possesses, but does not control. Though we cannot control it, we are interested in its every movement every hour. It may be pleasant in its aspects, or unpleasant; calm, or terrible; but man accepts it all just as he accepts himself. It is a part of ourselves, a part of every living thing, and it makes us all akin. It is the one common medium of universal understanding and sympathy. Men and nations may squabble and fight over many things; but the atmosphere-the weather is talked about and discussed more than anything else in the world, yet never a cross word! Think back over all the weather-talk you ever heard and you will remember that it was all in a spirit of friendliness and good will. This is really a significant fact in nature. The atmosphere is the most interesting thing in the world. About no other thing is all mankind so eager to know, to discover its secrets, to interpret its moods and phases. Therefore, we can conceive of no more universally appealing and thrilling scientific romance than a grand quest of the stupendous, mysterious old King Weather, who travels ceaselessly over the face of the entire globe, but has never yet been seen whole. We feel a slap of his hand here, a kick there, the surge of his great limbs on one continent, while his face smiles peacefully for a spell upon a distant sea or land; but always it is a partial view. He is with us everywhere every day, but no one sees more than a small part of his great hulk at any time. Yet he is an entity, and we must discover him as an entity, a unit, in order to understand more about him. The only way we can visualize him as a whole is by means of the world weather map, based upon systematic, synchronous observations over the whole globe. But, turning aside from the vision of the scientific romance of the project, let us think for a moment of the material, economic benefits that would result from reliable long-range weather forecasts. Probably the first great benefits would come to commerce, broadly speaking-to handlers of products exchanged between distant countries; for supply and demand, which depend so much upon the character of the seasons, could then be made more nearly estimated and much more safely regulated and prepared for than now. All the ramifications of trade would share in the benefits-the producer, the manufacturer, the transportation systems, the merchants, and the consumer. Secondly, the interests of agriculture the world over would be enormously served by reliable advance information as to the character of the seasons six months or a year ahead in the great crop producing areas; whether spring would be early or late; whether rainfall would be ample or drought prevail; what regions of the world would have favorable conditions for crops and what regions unfavorable. Thirdly, thousands of travellers and health seekers would value the advance information highly. Fourthly, the great service already rendered to navigation (on land, on sea, and in the air) would be greatly broadened and improved. In the aggregate, stupendous economic savings would result. Certainly, the investment necessary to carry on the meteorological work required to obtain the data for long-range forecasts would be a paltry sum as compared with the amount of savings. To get such observations and reports is the first problem. There would have to be a working plan; there would have to be money and instruments and men; there would have to be meteorological stations established in many far, isolated places, where none now exists; there would have to be men to take the observations and send reports by radio or wire from those lonely places. Dr. Charles F. Brooks, secretary of the American Meteorological Society, has suggested some things that might be undertaken if the necessary funds were available: 1. Publish a world weather map daily within six hours after the hour of observations. Have regional special stations for collecting reports. Have some of these special stations make daily forecasts for those parts of the world not now covered by international service. 2. Establish such weather stations, solar constant observatories and ocean observation points as may be required for the world weather map. Pay for necessary radio sending and receiving stations not already available. 3. Study world weather. Support two officially designated meteorologists from every international meteorological service, one at home and one at the headquarters. The duties of such meteorologists would be to collect and reduce climatic data on a uniform scale decided by the International Meteorological Committee. Employ enough investigators to study and compare the maps. Go into research on world weather. Compare world weather with daily solar constant. Summarize world weather by weeks and compare with solar constant, ocean temperatures, and snow cover, for example. Work back into earlier years for all parts of the world, both monthly and weekly. Develop forecasting, increasing accuracy and range of day to day forecasts, and extend long range forecasting. Difficult things to accomplish, these; but in a matter of such universal interest there are bound to be progress and development with a few years. There are already progress and development. The world is becoming rapidly consolidated in its interests and common pursuits. Former impossibilities of time and space are vanishing. Hence, our dream, that one of the greatest and most astounding achievements of all time awaits accomplishment in the not far distant future—a daily, detailed chart of the entire atmosphere near the earth's surface, which will result in the course of no long time in discoveries about the laws of the weather and climate that will be of the greatest interest and value to all the people of the world. THE SIXTEEN YEAR PERIOD IN CLIMATE Recently three entirely different lines of evidence have converged perfectly toward showing a period of fifteen or sixteen years in meteorological data, of much greater importance than any announced in any previous research. The first of these is a periodogram of the prices of wheat in England, published by Sir W. H. Beveridge1 in 1921. Beveridge has used prices from 1545 to 1844. The intensity of the peak at 15.3 years is nearly twice that found for any other period. Furthermore the intensity is the principal feature of both the periodograms, one from 1545 to 1694 the other from 1695 to 1844. Such continuity is unique in the search for periodicities. From the height of the peak Beveridge computes the frequency of accidental distribution as one in two and a half million. It is interesting to note, in the light of later papers, that he considers the lack of meteorological evidence of such a period. The second is the rainfall periodogram computed by the writer2 from 173 years of northern European records. In this periodogram, computed for periods from 8 to 48 years, one peak at 15 years dominates everything. Even measurement of the area under the periodogram as 1 Beveridge, Sir W. H.; Weather and Harvest Cycles, The Economic Journal, December, 1921, pp. 429-452. done by Schuster, shows the ratio of height of peak to mean height of periodogram as 5.83. If the mean height of the periodogram be computed by my equation3 Mean height = 1.099€2 where € is the probable error of one datum; allowance is made automatically for the fact that the distribution of points in the periodogram is not accidental and the ratio is very much increased, giving a probability comparable with that found by Beveridge. The third line of evidence is that just published by Arthur Wagner1 in Vienna. He has used temperature data from Vienna and other middle European stations, none of which has been used in either of the previous pieces of work. He finds from his periodogram, which embraces the years 1776-1919, a 16 year period with an amplitude of nearly 2.5C, a truly marvelous magnitude. Summer and winter each shows the periodogram separately, but with reversed phases, so that it is best found by considering summer minus winter. Each of these papers in itself contains almost incontrovertible evidence of the reality of the period. Their combined weight leaves no possibility of a mistake. Furthermore the amplitudes seem to be great enough that at last we have a meteorological period definite enough that it should command the serious attention of economists.—Dinsmore Alter, University of Kansas. May 8, 1925. * Alter, Dinsmore; Application of Schuster's Periodogram to Long Rainfall Records Beginning 1749, Monthly Weather Review, October, 1924. 3 Alter, Dinsmore; Equations Extending the Use of Schuster's Periodogram, Astronomical Journal No. 850, 1925. 4 Wagner, Arthur; Eine bemerkenswerte 16 jährige Klimaschwankung, Sitzungsberichte der Akademie der Wissenchaften in Wien, Mathem.-naturw. Klasse, Abteilung IIa, 133 Band, 5 und 6 Heft, 1924. PROTECTING ORCHARDS FROM FROST * By J. B. KINCER, U. S. Weather Bureau Mark Twain's classic observation that “everybody talks about the weather, but nobody does anything about it,” is no longer strictly true. Much is now being done about the weather, if not to control it, at least to protect against its unfavorable features. Among the many things that are being done about the weather at the present time is the protection of orchards from frost. The few minutes at our disposal for discussing this subject will be confined to citrus fruits, as protective measures are at present more extensive in this field than in others. In the early days of citrus growing in Florida, there happened to be a series of warm winters without damage from frost and, consequently, the industry was extended farther and farther north, until the Georgia border was reached in 1895. In that year, however, a disastrous freeze completely destroyed the groves over the northern portion of the state and since then the industry has been confined to the Peninsula, except in the case of the hardier varieties of oranges, known as satsumas. After the 1895 freeze, which reduced the citrus output of the state from Author's summary of paper presented at Washington meeting of the Society, May, 6,000,000 boxes in 1893 to 75,000 in 1895, more or less systematic efforts were made to protect the citrus groves from the cold. Heating was accomplished by a primitive method of building log fires, and this is still regarded favorably by some growers in that state. Recently, however, a coke burner has been introduced, but extensive protection by this, or any other method, is not practised. The principal reason for this is that the harmful freezes are comparatively infrequent in the main Citrus Belt. The satsuma, which is a hardy dwarf variety of orange, will withstand comparatively low temperatures, and large acreages of these have been recently set in the extreme northwestern portion of Florida and in southern Alabama. Considerable protection equipment has been provided in the latter state within the last year or two, but an opportunity has not, as yet, been afforded for testing the effectiveness of heating when low temperatures prevail in that section. Heating was first practised in California about 1896 in the form of burning coal. In 1910 the first oil heater came into use, the type being simply an open can or pot holding one or two gallons of oil. In 1911, however, many groves were successfully brought through a freeze by this method, and since that time the custom has increased rapidly. The general use of heaters was hastened by the disastrous freeze of 1913, when it was recognized that to maintain the citrus industry on a paying basis protection would have to be practised. Up to this time it was thought that the most effective protection was afforded by a blanket of dense smoke, but it was soon learned that the essential requisite was heat and not smoke, and in recent years efforts have been directed toward better combustion of oil, with a view to securing the maximum of heat and the minimum of smoke. In the past 15 years the advance has been from the open pot, providing practically an open fire, to the latest substantially constructed heater, with a capacity of 9 gallons of oil, well fitting draft regulators, and improved stacks, which reduces the amount of smoke to a minimum. These cost about $3 each, with about 50 required to the acre. There has been a great deal of trouble with the townspeople in southern California, as they strenuously object to the smoke produced by heating operations. While the modern heater produces a small amount of smoke in comparison with the early types, the number in use has increased so rapidly that this is still a vexing problem. The matter has been taken to the courts, and even the legislature petitioned for the enactment of laws prohibiting orchard heating in any part of the state. To be successful it is necessary that orchard heating be conducted systematically, with adequate equipment, and that a reserve of fuel be provided sufficient to meet any emergency that is likely to occur. As to operation, I think we can best get an idea of the importance of proceeding on a carefully prearranged plan in considering the technique of one of the most successful heaters in southern California. Should we visit this grove in midsummer we would see trucks conveying oil to fill the tanks that have been erected at convenient places as reservoirs for |