Great was the fright of not a few timid believers. Many arranged their affairs for the end of the world. Some, as the Millerites have several times done, prepared their ascension robes. Finally, the whole thing proved to be a hoax. A wag had endeavored to amuse himself at the expense of the public.
Such are fair specimens of predictions that continually appear in the newspapers. Certain men will always endeavor to astonish the ignorant by their words and works. Seldom do sober-minded people pay the least attention to them. As for minor changes in weather, they are so constant, and so limited in area, that, as stated elsewhere, any one is safe for announcing the character of the weather for any day in the year. From a score of places, he could obtain testimonials of the correctness of his prognostications; while nine score more, if they spoke, might declare him altogether mistaken.
But many will ask in all seriousness, if there is no means of prediction upon which all may depend. Is any more reliance to be placed upon the prognostications of the Signal Service than upon those of the self-constituted prophets?
A brief statement of the principles relied upon will be satisfactory on this point.
Our weather bureau was established in 1870. Such organizations are maintained, at the public expense, in Great Britain, France, Germany, Italy, Australia, Russia, India, Algeria, and Japan. Several smaller countries share in the expense and benefits. Men long trained in the work grow more reliable. Each must first master the topography and the prevailing movements of the atmosphere of any region, ere he can presume to know anything of the probable changes.
How extremely important a knowledge of the country is, will be understood when it is remembered that mountain ranges may turn aside great storms, and hills of any considerable size may modify small ones. And in general, storm paths are so narrow, in comparison with the whole country, that the slightest variation at the start may be very important at the end of six hundred or seven hundred miles—or a day’s travel. So, announcing twenty-four hours beforehand the exact locality a storm may reach is really a very delicate piece of work. If a tyro should announce rain for North Georgia, he might be astonished to find a difference of twenty-one per cent. between Atlanta and Augusta. He would find in Tennessee sixteen per cent. difference between Knoxville and Nashville; or twelve and a half per cent. in Iowa between Dubuque and Davenport.
The Signal Service does not endeavor to forecast entirely new conditions so much as to give warning of storms already on the way. It can not safely say where a storm will arise; but it can declare with tolerable certainty the path a storm will pursue after having once started.
Yet, there are certain signs of rain that can be of use to the public. Americans, as a rule, pay less attention to the actions of the animal kingdom at change of weather than other nations; and the lower animals detect changes of weather more quickly than man. Slugs and snails often leave their crannies, and endeavor to find some drier retreat at the approach of rain. Swallows fly lower; chiefly because the insects they pursue abandon the upper air. Crickets and grasshoppers become less noisy, and seek snug retreats. Fish leap more frequently from the water. The oft-praised tree-frog seems not to have deserved the confidence placed in him as a barometer.
Quatremere Disjonval, when made a prisoner of war by the Dutch, made a careful study of the habits of the house spider, while in confinement. His observations played an important part in the war. “General Pichegru, being prevented by the mild weather from carrying out his intention of invading that country, was about to retire with his army from the Dutch frontier, when Disjonval found means to inform him that, from the signs he had observed in his spiders, a severe frost was sure to take place in the next ten days. Pichegru trusted to the prognostic: the frost came in time. Holland was conquered, and Disjonval released from his prison.”
Voigt asserts that the spider is so reliable a barometer because of its anatomy: the long, slender, unmailed legs being peculiarly sensitive to atmospheric changes. That is, when Madam Spider finds herself with a touch of rheumatism, she wraps herself in a thicker blanket and takes to her den. In fine weather the garden spiders are much more plentiful; and the tiny gossamer spiders also are numerous, and fly at greater heights.