A tiny spot appears on the face of the sun.

Immediately a tornado rips a piece from the surface of the earth, 92,000,000 miles away!

Or a blizzard wraps a dozen states in its freezing arms!

Or a deluge of rain fills the beds of rivers and streams and hurls death and destruction everywhere!

No matter which of these happens—the storm king has somewhere obeyed the command that came to him from the sun—a lackey of Old Sol to jump the instant a button is pressed.

It was just such a spot, no doubt, on the far-flung sun, that caused the death-dealing tornado which has ripped this week a great hole in the middle of our map, killing hundreds of persons, splitting thousands of dwellings in twain and destroying millions in property.

How is it, you ask, that so distant a force as a speck on the glowing orb of day can bring such devastation to the "good ship Earth?"

Well, it is the investigations of Father Jerome S. Ricard, S. J., of the Santa Clara university, California, which have proven to the satisfaction of weather experts that sun spots are responsible for great storms on this globe. They, he has shown, cause changes of temperature which affects the earth’s atmosphere where it is most sensitive—at the equator and the poles. This, in turn, starts a whirl of air that develops in speed—and you have a great storm.

The natural question, then, is why is there a storm sometimes in Chicago, for instance, while there is none in Denver?

The answer sums up the entire matter of weather problems, for the conditions which control the local atmospheres of different sections are entirely different. Thus a spot which causes a deluge of rain in Louisiana simply makes the weather a bit hotter in Yuma, Arizona, or cooler at Washington, D. C.

The reason for this is that a sun spot has instant effect on two currents of air or whirls in the air, one from the north pole going south and one from the equator going north.

The storm is the battle between these two currents when they meet.

That battle MAY take place so high in the air that there is little or no effect felt on the surface of the earth.

Or they may meet on a battle plain near to us and a Violent storm—generally of tornado tendencies—ensues.

There are two general storm paths in the world—one north and the other south of the equator.

The northern path starts at the equator and moves northwestward so long as it remains south of the 30th parallel on a line with the city of New Orleans. Once across this line it turns and travels northeast until it spends itself or reaches the polar regions.

The same condition holds good with the southern path, except that the original direction is southeast and the change is to the southwest.

Sunspots having started air whirls from both ends of the path, the tendency of the southern whirl, being warmer, is to rise and of the northern whirl to stay close to the surface. If the northern current is thick enough, as it usually is in the winter time, the effect of the southern current will be lost. Anything that will send the southern current higher into the air will shield the country directly in front of it from the violence of the change of atmosphere it causes. Thus a mountain range will sometimes shoot the disturbing element so high that while a severe storm will take place on one side of the mountains, the other side is not affected at all.

Ohio's and Indiana's appeal for help.

A long stretch of flat country, however, will permit this southern current to settle down, if it happens to be very heavy, and so get closer to the earth.

That is one of the explanations given for the prevalence of severe storms in the prairie-like section of the United States between the Alleghenies and the Rockies.

It will be noticed that the most severe storms of this sort are met in the central section of this flat area, in Kansas, Missouri, Nebraska Illinois, Iowa, the Dakotas, Minnesota, Manitoba, and Saskatchewan and the western part of the province of Ontario.

The great lakes serve as a deflector of the currents in this country because of the excess of moisture in the air over these great bodies of water and the consequent heaviness of the atmosphere at these points. For that reason the storms on the lakes are greater and more frequent in winter than in summer because the northern current, which freezes and removes this moisture, has the easier time. The southern current being warmer and lighter naturally passes over the lakes at a high altitude, although, of course, it sometimes creates big disturbances.

By means of the daily reports received by telegraph at the weather bureau in Washington and in the weather services in all the European countries, in Japan and in the observatory in the Philippine islands, together with the wireless reports received from stations and ships, a rather accurate forecast of the conditions in the northern half of the world can be made.

This is possible because the observers are acquainted with the conditions in each locality where an observation is made and by close watch extending over a long period of years, are able to tell what certain recognized changes are likely to bring forth.

Thus if a storm, or whirl of air, is observed by one of the Philippine stations, the direction in which the whirl is traveling is noted and the forecaster in Japan can tell what effect it will have on Japan because he knows what effect similar whirls have had.

The weather man in Honolulu gets the report of the Japanese observer, together with the Philippine report, and he knows what these conditions have done to effect his country in the past and so advises his people, passing on his report to the Pacific coast, where the same system is followed throughout the entire United States.

In this way a storm can be followed from the time of its beginning until it blows itself out.

There are exceptions to these conditions of course. These are caused by purely local disturbances of the atmosphere which must be reckoned with to produce certain effects—which might change entirely the character of the effect of the battle of the upper air currents for supremacy, causing a severe storm or no storm at all.