Perhaps the most important result of the excess of rain was a rapid emigration to America beginning in 1846. In five years the popula tion diminished to 6,600,000, a loss of 20 per cent. During the suc ceeding dry favorable period the rate of emigration declined rapidly, as is shown in the accompanying table. In the eighties, however, another prolonged wet period with poor harvests made the bad social conditions still worse, and the people again flocked to America. If the climate of Ireland had been less variable, the important Irish element in the United States would still be here because of the con stant cause of emigration found in social and economic conditions, but it would presumably be much smaller than is actually the case.
How Rainfall Cycles Affect the American Farmer.—Too much rain and too little are both harmful, but in the United States more harm comes from too little than from too much. Corn illustrates this. The corn produced in the United States is worth over three billion dollars each year, or about as much as all the ores, metals, and other mineral products including coal, iron, petroleum, copper, gold, cement. and many other less valuable products. Its variations from year to year, however, are very great. For instance, in 1894 about one billion two hundred million bushels were raised, while in 1895 the crop was a billion bushels larger. Since corn was then worth 50 cents a bushel on the farm, the difference between the amount of money received by the farmers in those two years would be nearly $500,000, 000, which was as much as a billion now. There was a similar difference between 1901 and 1902, while differences of 300,000,000 bushels from one year to the next are common.
The chief cause of such variations is rainfall. Corn can get along with a small supply of moisture during the early and late parts of its life, but from the end of June to early August when the ears are swelling, plenty of water is essential. The great corn producing States of Ohio, Indiana, Illinois, Iowa, Missouri, Nebraska, Kansas, and Oklahoma with the corn growing parts of the neighboring States plant 80 to 90 million acres of corn each year. If the July rainfall of this area averages about 21 inches in one year and 31 in another the difference in the yield of corn is about 61 bushels per acre, or the huge amount of more than half a billion bushels. If the price on the farm is a dollar per bushel, the value of this one inch of rain is more then $500,000,000. Another inch of rain adds nearly half as much more to the value of the crop. It scarcely seems credible that a single inch of rain can produce such tremendous results, even though it covers such a large area. Surely rainfall is a geographic variable of almost unlimited power.
Luckily the whole country never suffers from deficient rainfall at one time. Yet there are years such as the early nineties when the deficiency of rain is very widespread. It was such a deficiency that caused the corn crops of 1894 and 1901 respectively to be worth half a billion dollars less than those of 1895 and 1902. Thus the income
of the average corn-raising farmer was reduced two or three hundred dollars.
Think what it means when not only the corn, but many other crops respond to abundant rainfall. Not only do the farmers prosper, but the railroads receive far larger sums than usual for the freight on the abundant crops and on the goods that are bought in exchange for them. The merchants prosper, for many more shoes, hats, suits, dresses, plows, clocks, knives, automobiles, and all sorts of manu factured goods are bought by the farmer in the good years than in the bad. Many factories also prosper, for since the farmers buy more goods than usual, the factories run on full time. Thus few people are out of work, and the manufacturing population as well as the farmers have more than the ordinary amount of money to spend. News papers and magazines are bought more frequently than at other times, moving pictures and other amusements are patronized with greater freedom. Moreover, many farmers who have been in debt are able to pay off their mortgages so that capital is available for new enter prises. Altogether the whole country feels a wave of prosperity which shows itself not only in business, but in quiet political condi tions, in great gifts for universities, hospitals, and other public institutions, and in a general feeling of satisfaction and encourage ment.
Ancient Climatic Cycles.—(1) Ruins as an Evidence of Decrease in Rainfall.—In past centuries climatic cycles seem to have gone to greater extremes than.those of our own day and to have been one of the important factors in the rise and fall of nations. The chief evidence of this is found in (1) ruins, (2) the level of salt lakes, (3) the growth of old trees. Palmyra in the Syrian Desert is one of the best examples of a ruin showing evidence of changes in climate. In the early cen turies of the Christian era Palmyra was a great city as large as modern Damascus, which has a population of 150,000. Ancient writers spe"ak with enthusiasm of its sweet water and beautiful gardens. Its caravans traveled all over western Asia, and it grew so wealthy that its rich citizens took pride in adorning it with wonderful colonnades and temples. To-day Palmyra is a vast desolate ruin in the midst of the desert, and harbors only a village of about 1500 people. Its water is still derived from the old aqueducts, but instead of being sweet and abundant, it has a disagreeable odor of sulphur, and is so scanty that the people cannot get enough, to irrigate even the small gardens on which they now depend. Such conditions not only here, but in hundreds of other places, seem to afford conclusive evidence that during the past 2000 years the progress of great climatic cycles has caused the rainfall and the population to dwindle. It may be that during the rainy portion of another cycle Palmyra will again become a great city.