which may be due to two motives—foresight and desire for profit.The first motive is by far the more powerful. To its action has been due the greater part of all wealth which has been saved. But the second motive is the chief cause of fluctuations in the amount of a nation's capital. Whether the amount of capital at any time existing in the country is above or below the average is almost entirely determined by the profit which it may be thought capital will realise. This profit may be estimated by the current rate of interest. But in political economy, as in many other sciences, the causes which produce the disturbing fluctuations require a more careful investigation than those causes whose action is more constant and more undeviating. The earth when revolving in its orbit is acted on by a great number of forces. It is attracted by every body in the planetary system, yet these forces combined are almost immeasurably inferior to the force of attraction which is exerted by the sun. Most important mathematical investigations, however, depend upon the action of these disturbing forces. Similarly, in political economy, the effects of the more constant causes can be readily estimated; but causes more varying in their action introduce fluctuations and disturbances which must be investigated and classified by the scientific principles of political economy.
Importance of the desire to accumulate wealth.As civilisation advances the desire to accumulate wealth increases, and foresight for the future becomes more general. The more men's intellectual and moral faculties are developed, the more careful will they be to make a reasonable provision for the future. The Jesuit missionaries, who in the eighteenth century formed a settlement in Paraguay, found the great difficulty they had to contend with was the utter recklessness of the people. The missionaries gave them seed. They knew that this seed would, if sown, in a few months yield them a plentiful supply of food, yet they could not be restrained from eating the seed instead of sowing it; the smallest present enjoyment was by them preferred to the greatest prospective advantage. People in such a condition can be very little superior to the more intelligent animals, whose hereditary instincts induce them to provide against danger which they may have to