Part 5

Sympiesometer 41

Temperature, correction for 27

Terrestrial radiation 13

Thermographs 23

Thermometer scales 20

„ screens 50

„ radiation 11, 14

„ standard 21

True bearings of wind direction 71

Vernier, principle of 30

„ setting the 31

Weather warnings 40, 44, 53, 54, 55, 56, 57, 58, 59, 60, 73, 77, 94

Wet and dry bulb hygrometer 50

Wind, registration of 85

„ gauges 79

„ scales 76, 83

„ vane 78

PREFACE.

The late Admiral Fitzroy entertained the opinion that the various phenomena which go to form what we call “weather” are “measurable at any place, and that having these measurements at various places over a given area, such as the British Isles, we ought to be able to foresee the peculiar results as regards the direction and force of air currents which have their distinctive weather characteristics in relation to temperature, rainfall, and electrical manifestations.”

A conviction of the soundness of this opinion has induced the writer to make the present compilation, in the hope that many who have hitherto avoided the subject of meteorology and the weather may find interesting matter, where before all seemed dull and technical.

Any attempt at rigid mathematical accuracy is disclaimed at the outset; the leading principles involved in weather forecasting and storm prevision will, however, be stated in a sufficiently definite manner to divest the subject of the mystery in which it has hitherto seemed to be enshrined, and thus enable the unscientific reader to become weather-wise, and casual observers to note weather phenomena with some degree of method and precision.

On page 4 will be found a list of works which have proved useful aids in making the present compilation. The writer desires to acknowledge his indebtedness to the various authors and publishers, and especially to Mr. Strachan, for permission to quote from his able pamphlet on “Weather Forecasts, and Storm Prevision,” and to reproduce the valuable table on page 37, for Calculating Heights of Mountains, from the fourth edition of his handy “Pocket Meteorological Register.”

The publication of Weather Reports in the daily journals must have convinced the most indifferent that much greater importance is now attached to weather phenomena than formerly; and this conviction will be deepened when it is remembered that a Parliamentary grant of £10,000 is annually expended in support of the Meteorological Office and its seven fully organized observatories in this country, while America expends no less a sum than £80,000 annually in the pursuit of weather wisdom; and the leading nations of Europe have also established meteorological observatories in suitable localities.

The balloon ascents of Messrs. Glaisher and Coxwell attracted much attention to the instruments used in estimating atmospheric phenomena, and awakened a desire to know something of the functions of a barometer, thermometer, hygrometer, &c., and especially of the classification of those important weather-warners, clouds. These subjects will be found duly noted in their order, and every phenomenon being traced to its source, Solar Radiation, it is hoped that these pages may prove generally acceptable, and be deemed not altogether unworthy of

“THE CLERK OF THE WEATHER.”

WEATHER WARNINGS.

The two great Forces of Nature are Gravitation and Heat, which always act in opposition to each other.

WEATHER is the result of the action of these forces on matter, and where one form of force is in excess of another, changes are produced which become apparent to our senses, or are indicated by suitable instruments.