The Mentor: The Weather Part 4

BELMORE H. BROWNE, Artist, Author and Explorer.

FRANK WEITENKAMPF, of the New York Public Library, Expert In Prints.

W. J. HOLLAND, Director of the Carnegie Museum, Pittsburgh, Pa., and distinguished Naturalist.

DEAN C. WORCESTER, noted Traveler and Lecturer and Author.

AYMAR EMBURY, well-known Architect and Writer on architectural subjects.

C. F. TALMAN, of the United States Weather Bureau, Was.h.i.+ngton.

Complete Your MENTOR LIBRARY

SUBSCRIPTIONS ALWAYS BEGIN WITH THE CURRENT ISSUE

The following numbers of The Mentor Course, already issued, will be sent postpaid at the rate of fifteen cents each.

Serial No.

1. Beautiful Children in Art 2. Makers of American Poetry 3. Was.h.i.+ngton, the Capital 4. Beautiful Women in Art 5. Romantic Ireland 6. Masters of Music 7. Natural Wonders of America 8. Pictures We Love to Live With 9. The Conquest of the Peaks 10. Scotland, the Land of Song and Scenery 11. Cherubs in Art 12. Statues With a Story 13. Story of America in Pictures: The Discoverers 14. London 15. The Story of Panama 16. American Birds of Beauty 17. Dutch Masterpieces 18. Paris, the Incomparable 19. Flowers of Decoration 20. Makers of American Humor 21. American Sea Painters 22. Story of America in Pictures: The Explorers 23. Sporting Vacations 24. Switzerland: The Land of Scenic Splendors 25. American Novelists 26. American Landscape Painters 27. Venice, the Island City 28. The Wife in Art 29. Great American Inventors 30. Furniture and Its Makers 31. Spain and Gibraltar 32. Historic Spots of America 33. Beautiful Buildings of the World 34. Game Birds of America 35. Story of America in Pictures: The Contest for North America 36. Famous American Sculptors 37. The Conquest of the Poles 38. Napoleon 39. The Mediterranean 40. Angels in Art 41. Famous Composers 42. Egypt, the Land of Mystery 43. Story of America in Pictures: The Revolution 44. Famous English Poets 45. Makers of American Art 46. The Ruins of Rome 47. Makers of Modern Opera 48. Durer and Holbein 49. Vienna, the Queen City 50. Ancient Athens 51. The Barbizon Painters 52. Abraham Lincoln 53. George Was.h.i.+ngton 54. Mexico 55. Famous American Women Painters 56. The Conquest of the Air 57. Court Painters of France 58. Holland 59. Our Feathered Friends 60. Glacier National Park 61. Michelangelo 62. American Colonial Furniture 63. American Wild Flowers 64. Gothic Architecture 65. The Story of the Rhine 66. Shakespeare 67. American Mural Painters 68. Celebrated Animal Characters 69. j.a.pan 70. The Story of the French Revolution 71. Rugs and Rug Making 72. Alaska 73. Charles d.i.c.kens 74. Grecian Masterpieces 75. Fathers of the Const.i.tution 76. Masters of the Piano 77. American Historic Homes 78. Beauty Spots of India 79. Etchers and Etching 80. Oliver Cromwell 81. China 82. Favorite Trees 83. Yellowstone National Park 84. Famous Women Writers of England 85. Painters of Western Life 86. China and Pottery of Our Forefathers 87. The Story of The American Railroad 88. b.u.t.terflies 89. The Philippines 90. Great Galleries of the World: The Louvre 91. William M. Thackeray 92. Grand Canyon of Arizona 93. Architecture in American Country Homes 94. The Story of The Danube 95. Animals in Art 96. The Holy Land 97. John Milton 98. Joan Of Arc 99. Furniture of the Revolutionary Period 100. The Ring of the Nibelung 101. The Golden Age of Greece 102. Chinese Rugs 103. The War of 1812 104. Great Galleries of the World: The National Gallery, London 105. Masters of the Violin 106. American Pioneer Prose Writers 107. Old Silver 108. Shakespeare's Country 109. Historic Gardens of New England

NUMBERS TO FOLLOW

July 15. AMERICAN POETS OF THE SOIL. _By Burges Johnson, a.s.sociate Professor of Literature, Va.s.sar College._

August 1. ARGENTINA. _By E. M. Newman, Lecturer and Traveler._

[Ill.u.s.tration: CENTRAL OFFICE OF THE UNITED STATES WEATHER BUREAU, WAs.h.i.+NGTON, D. C.]

WEATHER SERVICES AT HOME AND ABROAD

Monograph Number One in The Mentor Reading Course

Posted up in public offices, in hotel corridors, and other conspicuous places in our cities, the official weather map is a familiar sight. Even more familiar is the official weather forecast, displayed, as a rule, on the first page of the daily newspaper, and sent broadcast over the country on the little brown cards which one may see in the village postoffice as well as in the city drug-store. When a great storm sweeps over land or sea, detailed official reports concerning its progress and characteristics are published in the daily press. When a lawsuit involves a dispute as to the temperature or the state of the sky on a certain day, the official weather records are consulted.

How much do you know about the branch of the national government that is charged with the duty of keeping watch of the weather--recording its vagaries as they occur, and also predicting them, as far as is humanly possible?

Besides its office in Was.h.i.+ngton, where more than two hundred persons are constantly employed, the Weather Bureau has about two hundred stations, manned by professional meteorologists and observers. One of these will be found in almost every large city, while some are in towns of very modest importance. A regular Weather Bureau station is well worth a visit. The instrumental equipment of these stations is almost superhuman in the accuracy with which it sets down on paper the chronicle of weather happenings from day to day and from moment to moment. Little less marvelous is the system by means of which weather information--past, present and future--is disseminated from these official foci. The postoffice, the telephone, the telegraph (wire and wireless) are all pressed into service to the fullest extent--especially in giving timely notice of approaching storms and other destructive forms of weather. These agencies are supplemented by visible and audible signals, in the shape of flags, lanterns, railway whistles and so forth.

Contrary to popular belief, the Weather Bureau does not exist primarily for the purpose of telling the public (with a considerable margin of uncertainty) whether it will be advisable, on the morrow, to carry an umbrella or wear an overcoat. The important work of the Bureau is twofold. It consists, first, in the prediction of those atmospheric visitations, such as storms, floods, and cold waves, which endanger life and property on a large scale; and, second, in the maintenance of the records that form the basis of climatic statistics. In both these directions the Bureau splendidly justifies its existence.

Our national weather service was founded in 1870, and for twenty years was maintained by the Signal Corps of the Army. In 1890 it was established on the present basis, as the Weather Bureau of the Department of Agriculture.

Most civilized countries possess official services for the observation and prediction of weather, though no other is organized on quite so grandiose a scale as ours. The British Meteorological Office, the Prussian Meteorological Inst.i.tute, the Central Meteorological Bureau of France, and the Central Physical Observatory of Petrograd are among the leading inst.i.tutions of this character in the Old World. Admirable weather services also exist in India, j.a.pan, Australia, Canada, Argentina and elsewhere.

[Ill.u.s.tration: A SIMPLE WEATHER STATION]

METEOROLOGICAL INSTRUMENTS

Monograph Number Two in The Mentor Reading Course

The history of meteorological instruments dates back at least as far as the fourth century before the Christian era, when the depth of rainfall was measured in India by some form of gauge. We again hear of rain-gauges being used in Palestine in the first century of the present era. Thermometers with fixed scales were used in Italy in the seventeenth century, and the great Galileo, born in Pisa in 1564, took part in perfecting these instruments. Wind-vanes were known to the ancients. The earliest one of which we have any record surmounted the famous Tower of the Winds at Athens. In the Middle Ages the weatherc.o.c.k became the usual adornment of church steeples. The barometer was invented by Torricelli in 1643.

Most meteorological instruments, however, are of quite recent origin, and this is true especially of these types of apparatus that make automatic records, thus replacing, to a large extent, the human observer.

Our picture on the other side of this sheet shows the instruments used by the "co-operative" observers of the Weather Bureau. These observers, of whom there are about 4,500, well distributed over the country, serve the government without pay, and their painstaking observations have alone made possible a detailed survey of our climate. In the picture we see, on the right, an ordinary rain-gauge, and, on the left, a thermometer-screen containing two thermometers; viz., a maximum thermometer, for recording the highest temperature of the day, and a minimum thermometer, for recording the lowest. The screen, which is of wood, painted white, serves to s.h.i.+eld the instruments from the rays of the sun, while permitting free ventilation. Under these conditions the thermometers show the temperature of the _air_; whereas when exposed to direct sunlight a thermometer shows the temperature acquired by the instrument itself, and this may differ materially from the air temperature.

In contrast to this simple equipment, we find at a regular meteorological station, or observatory, an impressive collection of apparatus for observing and recording nearly all the elements of weather. The pressure of the air is measured by the mercurial barometer, and registered continuously by the barograph; the temperature of the air is automatically recorded by the thermograph. Other self-registering instruments maintain continuous records of the force and direction of the wind, the amount and duration of rainfall, the duration of suns.h.i.+ne, the humidity of the air, etc. There are also instruments for measuring evaporation, the height and movement of clouds, the intensity of solar radiation, the elements of atmospheric electricity, and various other phenomena of the atmosphere.

[Ill.u.s.tration: A MAJESTIC c.u.mULUS CLOUD]

CLOUDS AND RAINFALL

Monograph Number Three in The Mentor Reading Course

The International Cloud Cla.s.sification, now generally used by meteorologists, is an amplification of one introduced by an ingenious English Quaker, Luke Howard, in the year 1803. Howard distinguished seven types of cloud, to which he gave the Latin names _cirrus_, _c.u.mulus_, _stratus_, _cirro-c.u.mulus_, _cirro-stratus_, _c.u.mulo-stratus_, and _nimbus_. In pa.s.sing, it may be of interest to note that, a few years after Howard's cla.s.sification was published, an attempt was made by one Thomas Forster to introduce "popular"

equivalents of these terms. Forster proposed to call cirrus "curlcloud,"

c.u.mulus "stackencloud," stratus "fallcloud," etc. In other words, he a.s.sumed that because Howard's names were Latin in form they were unsuitable for use by the layman, and therefore needed to be supplemented by English names--although the proposed subst.i.tutes were, on the whole, somewhat longer and more difficult to p.r.o.nounce than the originals! A parallel undertaking would be an attempt to discourage the public from calling the wind-flower "anemone," or virgin's bower "clematis." Forster's superfluous names have never taken root in our language.

The highest clouds--cirrus and cirro-stratus--are feathery in appearance, and consist of minute crystals of ice. Their alt.i.tude above sea-level averages about five miles, but is frequently much greater than this. All other clouds are composed of little drops of water--not hollow vesicles of water, as was once supposed. Neither crystals nor drops actually "float" in the air. They are constantly falling with respect to the air around them, though, as the air itself often has an upward movement, the cloud particles are not always falling with reference to the earth. In any case, their rate of fall depends upon their size, and in the case of the smaller particles is very slow. Under some conditions the particles evaporate before reaching the earth, while under others they maintain a solid or liquid form and const.i.tute rain or snow. A fog is a cloud lying at the earth's surface.

Rainfall is one of the most important elements of climate, chiefly because of its effects upon vegetation. It is measured in terms of the depth of water that would lie on the ground if none of it ran off, soaked in, or evaporated; and this is, in practice, determined by collecting the rain, as it falls, in a suitable receiver, or rain-gauge.

Usually the gauge is so shaped as to magnify the actual depth of rainfall, in order to facilitate measurement. Snow is measured in two ways; first, as snow, and, second, in terms of its "water equivalent."

The latter measurement is commonly effected by melting the snow and pouring it into the rain-gauge, where it is measured as rain. By this expedient we are enabled to combine measurements of rain and snow, in order to get the total "precipitation" of a place during a given period.

Nature is notoriously partial in her distribution of this valuable element over the earth. A region having an average annual rainfall of less than ten inches is normally a desert, though irrigation or "dry-farming" methods may enable its inhabitants to practice agriculture.

The heaviest average annual rainfall in the United States (not including Alaska) is about 136 inches, in Tillamook County, Oregon. The rainiest meteorological station in the world is Cherrapunji, India, with an average of about 426 inches per annum.[B]