The second phase of the question, “what signs usually precede such periods?” opens a wide field for the student of speculative changes. Some inspiration may be gained from an examination of the two points already considered, i.e.: priority of price movements and business inflation; but it would be extremely difficult to use them as guides unless many other factors were given consideration. If we eliminate the element of periodicity, any attempt to determine the turning point by examination of advances in prices of stocks or volume of production and consumption of commodities is futile. Using pig iron as a barometer we might, after production has gradually increased from 8,623,127 tons in 1896, to 15,878,354 in 1901, argue that a considerable reaction was due in this line, but we would be out in our calculations two years and two million tons. Neither can we accept the simple fact of a decline, or the beginning of a decline in iron or in any other single commodity as indicating lower prices for stocks; for however accurate iron may be as a barometer of general business, it is not at all a barometer of the stock market. It is practically certain that stock prices will move either to higher or lower prices long before any reasons for such movements are apparent to the ordinary observer. Future stock market movements are largely deductive, and are not founded upon ordinary industrial statistical evidence. There is, however, one method by which some light may be thrown upon the subject of probable movements. A careful study of monetary conditions and expansion of credits will frequently reveal dangers not apparent in any other direction. It is scarcely necessary to say that such examination must not be confined to one quarter, such as New York City; or to one country, such as the United States. A comprehensive view of the world’s monetary conditions will be necessary. This subject is dealt with more fully in another chapter.