WEATHER-MAKING
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.