Meteorologists, in their candid moments, have been heard to express disappointment over the amount of progress made in the art of weather forecasting during the past half-century. “Shall we ever,” they ask, “be able to predict the weather with mathematical certainty, as the astronomer predicts an eclipse of the sun or moon?”

Perhaps even within the meteorological fold there are unorthodox optimists who would answer such a question thus: “Yes, because some day we shall control the weather. It is inconceivable that man, who is every day achieving new miracles in the conquest of nature, should not eventually find a way of regulating the rainfall and sunshine that are of such vital importance to his crops, the winds that must be reckoned with in his voyages by sea and air, and the various other elements of weather that have so much to do with his happiness and welfare. The attainment of this object is so tremendously desirable that it cannot forever baffle human ingenuity.”

In support of such a bold assertion it might be pointed out that we already control the weather to a certain limited extent. When the horticulturist burns orchard heaters to protect his fruit from frost he certainly alters the weather for a few hours over a small area of the earth. If there were any practical justification of the process, the temperature of the air over an entire State, for example, could be raised throughout the winter, with appreciable effects on agriculture. The difference between heating a single orchard for a night and heating a State for a season is one of degree, and not of principle.

The climate of a city is, through causes dependent upon man, materially different from the natural climate of the surrounding country. Every dwelling provided with heating arrangements enjoys an artificial summer amid the blasts of winter. Local control of the winds is exemplified in the planting of thousands of miles of trees as windbreaks in the prairie regions of our Middle West. By moderating the winds this process has a marked effect on temperature and evaporation and is so beneficial to crops that in the aggregate it furnishes a striking example of successful “weather-making” by mankind. Analogous methods, perfectly feasible with means already at our disposal, would change the whole climatic aspect of large areas of the earth’s surface.

The question “Can we make it rain?” may be answered in the affirmative by those who are neither impostors nor victims of self-delusion. The deposit of spray from the spout of a teakettle might, without much stretching of terms, be described as a miniature artificial rainstorm; but much bigger showers, in nowise different from those occurring in nature, can also be produced artificially. Huge clouds have often been observed to form over forest fires and other great conflagrations. These clouds, composed of water drops, tower far above the smoke cloud, and are identical in character and mode of origin with the cumulus and cumulo-nimbus clouds formed by currents of moist air rising from the heated ground on a summer day. There are several well-authenticated cases in which rain has been seen to fall from such clouds, and these showers have sometimes been so heavy as to extinguish the fires that generated them. Hence, given favorable conditions of humidity, temperature and wind, mankind can certainly produce a rainstorm (and perhaps a thunderstorm into the bargain) by the relatively simple process of building a big fire.

Unfortunately the vast majority of methods whereby man has attempted to regulate the weather have no such rational foundation as those we have just mentioned. Some are wholly superstitious, others are purely empirical, and yet others are based upon ideas that their promoters suppose or pretend to be scientific, but that are actually fallacious.

In the history of superstitious practices weather-making plays a prominent part. Sir J.G. Frazer, in that great storehouse of myth and folklore, “The Golden Bough,” says: “Of the things which the public magician sets himself to do for the good of the tribe, one of the chief is to control the weather and especially to insure an adequate fall of rain. In savage communities the rain-maker is a very important personage; and often a special class of magicians exists for the purpose of regulating the heavenly water supply.” Frazer devotes ninety pages of his work to a rapid survey of the superstitious methods of controlling the weather that have found credence among the various races of mankind. These range all the way from the most complicated ceremonies to the summary expedient of throwing a passing stranger into a river to bring rain.

The sailor who whistles or scratches the mast to raise a wind is merely keeping up a quaint custom, in the efficacy of which he may or may not put some lingering faith, but which the world at large long since ceased to take seriously. When, however, a vessel master attempts to disperse a waterspout by firing a cannon at it, he is doing what nine educated persons out of ten would probably do under the circumstances. Yet one process is no more futile than the other, and both are based on superstition. Ages ago sailors sought to frighten waterspouts away by pointing knives at them, or by shouts and the clashing of swords, and the use of cannon originally embodied the same idea of terrifying the watery monster. It is our purpose in the present chapter to describe especially several processes of weather-making which, while not obviously chimerical from the point of view of the layman, have been more or less positively discredited through the scrutiny of men of science.

The efforts of modern weather-makers have been directed especially to two objects; viz., the production of rain and the prevention of hailstorms. In the United States a certain amount of ingenuity has also been devoted to the task of dispelling tornadoes. Some years ago a device for the latter purpose was patented, consisting of a box, containing explosives, mounted on a pole and erected a mile or so to the southwestward of the village to be protected from these unwelcome visitors. The force of the wind was expected to detonate the explosives by driving a movable board against percussion caps. The inventor believed that a violent explosion would disperse the passing tornado funnel. Apart from the fact that a single installation of this character, or even several of them, would seldom happen to be at exactly the right spot to explode close to the relatively small vortex of a tornado, the effect of the explosion, even in the very heart of the storm, would certainly be negligible. The energy that keeps the tornado in action is supplied continuously from a level far above the earth, while the disturbance due to the explosion would be only momentary. Above all, the energy developed in any discharge of explosives that the community could afford to pay for would be quite insignificant compared with that which prodigal nature supplies to the tornado.

The same disproportion between the giant forces at work in the atmosphere and the pygmy forces at the disposal of mankind is a point that is overlooked in most attempts at weather-making.

The widespread belief that rain can be produced by explosions rises so far above the level of ordinary popular delusions that it has sometimes led to large expenditures of money on the part of drought-ridden communities and even of national governments. Perhaps the most remarkable example of official confidence in the efficacy of this process was that furnished some years ago by the Volksraad, or legislative assembly, of the Transvaal, which passed a law forbidding the bombardment of the clouds to produce rain, on the ground that the rain-makers were thwarting the will of the Almighty!

One manifestation of the belief in question is found in the common assertion that rain is the usual sequel of battles. This idea originated, however, long before the invention of gunpowder. It is mentioned by Plutarch and other writers of antiquity. Whatever superstition or crude process of reasoning may have first given support to this notion in the popular mind, the explanation now commonly advanced is that the condensation of moisture is promoted by the concussion due to cannonading, or that the drops already condensed and constituting the clouds are jostled together by the same disturbance, with the result that they coalesce and fall as rain. There is no ground for such assumptions. As was once pointed out by the late Professor Simon Newcomb, the effect of a violent explosion upon a body of moist air a quarter of a mile distant is about the same as that which the clapping of one’s hands would produce upon the moist air of the room in which the experiment is performed. Again, if we stand in the steam escaping from a teakettle and clap our hands we shall not produce a shower, though we jostle the water drops much more than the explosion does at a distance of a quarter of a mile.

In recent years another explanation has been offered for the alleged production of rain by explosions; viz., that the smoke and gases arising from an explosion increase condensation by increasing the number of “nuclei” in the atmosphere. As we have seen, however, in considering the natural formation of rain, the number of condensation nuclei normally present in the atmosphere is so great that it must be diminished, rather than increased, before drops as large as raindrops can be formed. Moreover, the nuclei required for the condensation of water vapor, including molecules of highly hygroscopic gases, are given forth in abundance by great manufacturing centers, yet these places do not have a heavier rainfall than the surrounding country. Pittsburgh, for example, is actually one of the driest places in Pennsylvania.

One obvious reason why rain often follows a battle is that battles are frequently fought in regions where rain normally occurs every two or three days, on an average, whether in peace or war. In northern France, for example, where the battles of the World War were plenteously interspersed with showers, meteorological records show that the average number of rainy days per annum is upward of 150. The drenching rains that made “Virginia mud” a byword during the American Civil War gave great currency to the belief in “rain after battles,” Here, again, we have accurate weather records to help us dispel a fallacy. Thus at Richmond rain falls on 122 days in an average year, at Lynchburg on 124 days, and at Petersburg on 105 days.

There is, however, a particular reason why rain is rather more likely to occur soon after a battle than shortly before one; viz., the fact that intervals of fair weather, with consequent dry roads, are used by commanders in carrying out the movement of troops that precede an engagement. By the time such arrangements, often occupying several days, are completed, the “spell” of fine weather is likely to be over, and a rainstorm is due in accordance with the normal program of nature.

The most famous undertaking in the history of rain-making—and one which has had an incalculable effect in fostering the credulity of the public with respect to similar enterprises—was that carried out by General Robert Dyrenforth on behalf of the United States Government in 1891. Congress voted appropriations amounting to $9,000 for these experiments, and Dyrenforth was appointed a “special agent” of the Department of Agriculture to direct them. After some preliminary trials in the suburbs of Washington, the experimenters proceeded to a ranch near Midland, Texas. Here a few balloons filled with a mixture of oxygen and hydrogen, as well as several sticks of dynamite carried up by kites, were exploded in the air, but the only explosions of considerable magnitude were set off on the ground. The experiments continued over a period of three weeks and in some cases showers fell within a few hours after an explosion, but, in spite of the somewhat favorable tone of the official report, the consensus of scientific opinion was that the undertaking was a failure, while the views of the public at large were divided. The attitude of the Government is sufficiently indicated by the fact that it has never since undertaken experiments in this line. The one tangible outcome of this affair was that a crop of private rain-makers sprang up all over the country, and to this day the example set by the official experimenters is cited in support of every sort of harebrained scheme for juggling with the weather.

In 1911 and 1912 the late C.W. Post, of breakfast-food fame, expended many thousand pounds of dynamite in efforts to produce rain in Texas and Michigan. Showers undoubtedly occurred in conjunction with Post’s experiments, but conditions favoring their occurrence were plainly indicated on the current daily weather maps, and they had been duly forecast by the Weather Bureau.

The professional rain-maker does not generally resort to the expensive process of bombarding the clouds. His methods most frequently involve the use of chemicals, and the details are shrouded in mystery. For example, about a quarter of a century ago one Frank Melbourne, known as “the Australian rain-maker,” enjoyed great celebrity and coined money by his exploits in this field. His plan was to shut himself up in a barn, freight car, or other structure, and manipulate his chemicals and electric batteries for hours or days. Naturally rain sometimes came after these operations, but as often it did not.

Several of the methods that have been suggested from time to time for producing rain are sufficiently discredited by the fact that the expense of putting them into execution would more than offset any benefits derived from the rain, if the experiments proved successful. Thus one genius, observing the deposit of water on the outside of an ice pitcher in a warm room, proposed to set up a barrier packed with ice in the path of moisture-bearing winds. Another plan occasionally suggested is to sprinkle the atmosphere aloft with liquid air or liquid carbon dioxide, in order to lower the temperature, by the rapid evaporation of these substances, below the point of condensation. A third proposal is to create a local updraft of air by means of powerful fans or blowers, thus imitating the convectional process by which clouds and rain are formed in nature.

Lastly, various plans have been suggested for altering the electrical condition of the upper atmosphere—for example, by electrical discharges from balloons—on the assumption that rainfall might thus be promoted. This assumption, however, is not consistent with known facts as to the relation between atmospheric electricity and the condensation of atmospheric water vapor.

While in America a vast amount of money has been wasted on futile experiments in rain-making, far more has been spent in Europe on schemes for averting hailstorms. Methods of accomplishing this purpose have varied from age to age. In antiquity it was the custom to shoot arrows or hurl javelins toward the gathering clouds in the hope of frightening them away. In the Middle Ages ecclesiastical or occult agencies were invoked; “hail crosses” (such as are still seen in the Tyrol) were erected; and the ringing of church bells was considered efficacious against both hail and lightning, as is shown by the inscriptions found on many old bells.

The custom of firing cannon at the clouds to avert hail began centuries ago in Styria and northern Italy, and it was well established in France before the Revolution. Toward the end of the eighteenth century, however, another method of hail protection was introduced in France, whence it spread over the rest of Europe. This consisted in setting up tall, metal-tipped poles, imitated from lightning rods. It was supposed that these poles, which were known as paragrÊles, would draw the electric charge from the clouds and thereby (though nobody could say why) would prevent the formation of hailstones. This device, though reported on unfavorably by the French Academy of Sciences, gained great popularity. One of its advocates, writing in 1827, states that more than a million paragrÊles were at that time in use in France, Switzerland, Italy, Austria, Bavaria, and the Rhine country. The vogue enjoyed by these contrivances is said to have come to a sudden end when a tremendous hailstorm not only devastated the fields and vineyards they were supposed to protect, but also knocked down a great number of the rods themselves.

In recent times both the hail cannon and the paragrÊle have been revived. The new era of “hail-shooting,” as the process of cannonading the hail clouds is called, dates from the year 1896, when a number of cannon of a new type were installed in the vine-growing district of Windisch-Feistritz, in Styria. The success claimed for them in this region led to their introduction on a vast scale over the greater part of southern and central Europe. The cannon employed were small mortars, to the muzzles of which were attached sheet-iron funnels. No projectile was used, but the explosion of the charge sent aloft a curious whirling ring of smoke and gas, powerful enough to splinter sticks and kill small birds several hundred feet from the cannon. By the year 1900 at least 10,000 hail cannon were in use in Italy alone. Several modifications of the device were introduced, such as the use of acetylene in place of gunpowder; and eventually certain forms of rocket and bomb were adopted, for concentrating the effects of the explosion at as high a level as possible.

About the year 1899 a new form of hail rod was introduced in France, and this has become the favorite means of protection against hail in that country. It is essentially a very large lightning rod of pure copper, grounded by means of a broad copper conductor. Such rods have been installed, in some cases, on church steeples and other tall edifices, including the Eiffel Tower, in Paris, and in other cases on tall steel towers erected for this purpose. This device is called fantastically an “electric Niagara,” because, according to the claims of its promoters, it draws down “torrents” of electricity from the clouds. Hundreds of these “Niagaras” have been constructed in France. Some of them are set up in rows, or so-called barrages, across the habitual paths of hailstorms. The French Government was induced to appoint a “ComitÉ de DÉfense contre la GrÊle” (Hail-protection Committee), which before the war had made elaborate plans for “protecting” not only the whole of France, but also Algeria and Tunis, with these devices. Similar rods have been erected in Argentina, and plans for introducing them in South Africa were near consummation at the time the World War broke out.

In order to understand the extraordinary hold that the various hail-protecting devices have taken upon the minds of European cultivators it should be remembered that the intensive cultivation of the soil is the rule over the greater part of Europe, so that a hailstorm of relatively small extent often does enormous damage. Vineyards are especially subject to injury from this cause, and many of the richest vine-growing districts of the Old World are notoriously afflicted with hailstorms.

Scientific commissions appointed by the Austrian and Italian governments conducted long series of tests of the methods of bombarding the clouds with mortars, bombs, and rockets, and declared them to be of no value. The erection of hail rods, though it has received a certain amount of official encouragement in France, is also strongly discountenanced by the majority of scientific men, as well as by a large proportion of intelligent agriculturists. Reports on the actual operation of the rods support conflicting opinions—as might be expected from the fact that the hailstorm is a decidedly erratic phenomenon. Thus, some observers claim that the storm clouds change conspicuously in appearance as they approach a “Niagara,” and if they shed hail upon the spot it is in a soft and harmless form. Others deny the accuracy of these observations, and point to the stubborn fact that ordinary hail has fallen on several of the rods themselves, including the one on the Eiffel Tower. In the suburbs of Clermont-Ferrand a “Niagara” is installed on an iron tower, 100 feet high. This rod was pelted with hail twice in 1912 and four times in 1913, and in one case the hailstones attained the size of hen’s eggs! Nobody has ever offered any plausible scientific hypothesis to explain why these rods should have an effect upon hail, even if they are able, as seems unlikely, to reduce the electrical charge of the clouds; since the formation of hail is due to movements of the air, which, in turn, are the cause and not the result of the charge in question.

Fortunately for the farmer and the horticulturist—especially in Europe—a method of averting the losses due to hailstorms is available in the shape of insurance, and its cost is decidedly less than that entailed in systematic hail-shooting or in the general erection of hail rods. Hailstorm insurance has been extensively practiced in the Old World since the end of the eighteenth century. In some countries it has been conducted or subsidized by the government. Generally each country is divided into a number of zones, according to the recorded frequency of hailstorms, and the premiums vary proportionately. Premiums also vary for different crops, since some are better able to withstand the effects of hail than others. The amount of insurance of this kind carried in Germany, alone, shortly before the World War, was more than $800,000,000.

Hailstorm insurance is fairly common in the United States, especially in the Middle West, but still lacks an adequate statistical basis in the shape of detailed records of hail frequency. In 1919 growing crops in this country were insured against hail to the extent of $559,134,000. Much information on this subject will be found in V.N. Valgren’s “Hail Insurance on Farm Crops in the United States” (U.S. Dept. of Agriculture, Bulletin 912), published in 1920.

Besides the weather-making schemes already noted, mention should be made of certain more ambitious projects of this character that have been bruited from time to time, and that have found plenty of credulous supporters. In the year 1845 an American meteorologist of undoubted ability, but much inclined to the riding of hobbies—viz., James P. Espy—proposed the building of great fires in the western part of the United States in order to regulate the winds and rainfall to the eastward. The fires were to extend in a line of six or seven hundred miles from north to south, and were to be set off once a week throughout the summer. Another genius, of less celebrity, proposed to destroy blizzards by means of a line of coal stoves along the northern boundary of the country. A favorite idea of those who aspire to produce wholesale changes of climate is to alter the course of ocean currents for this purpose. One early plan contemplated the damming of the Strait of Belle Isle in order to improve the climate of New England and the Canadian provinces; while, a few years since, a proposal to build an immense jetty eastward from Newfoundland for the purpose of “protecting the warm north-flowing Gulf Stream from the onslaughts of the ice-cold, south-flowing Labrador Current” actually received, serious attention from the Congress of the United States.