Such traders are suffering merely from youth, or lack of sound business sense, or both. They have a considerable period of study before them, if they persist until they get permanently profitable results. Most of them, of course, do not persist. A much more intelligent class, many of whom are properly to be considered as investors, do not allow their position in the market to blind them so far as current news or statistical developments are concerned, but do permit themselves to become biased in regard to the most important factor of all—the effect of a change in the price level. They bought stocks in the expectation of an improved situation. The improved situation comes and prices rise. Nothing serious in the way of bear news appears. On the contrary, bull news continues plentiful. Under these conditions they see no reason for selling. Yet there may be a most important reason for selling—namely, that prices have risen sufficiently to counterbalance the improved situation—and they would see and appreciate this fact if they were in the position of an uninterested observer. One of the principal reasons why investors of this class allow themselves to become confused as to the influence of the price level is because a bull market nearly always goes unreasonably high before it culminates. The investor has perhaps, in several previous instances, sold out at what he thought was a fair price level, only to see the public run away with the market to a point where his profits would have been doubled if he had held on. It is in such cases that an expert knowledge of speculation is essential. If the investor has not this knowledge, and cannot obtain the dependable advice of one who has it, then he must content himself with more moderate profits and forego the expectation of getting the full benefit of the advance. But with a fair knowledge of speculative influences, he can fix his mind on the development of the campaign, regardless of his own holdings, and can usually secure a larger profit than if he depended merely upon ordinary business “common sense.” The mistake is made when, without any expert knowledge of speculation, he permits himself to hold on in the hope of higher prices after a level has been reached which has fairly discounted improved business conditions. Not one trader in a thousand ever becomes so expert or so seasoned as to entirely overcome the influence his position in the market exerts upon his judgment. That influence appears in the most insidious and elusive ways. One of the principal difficulties of the expert is in preventing his active imagination from causing him to see what he is looking for just because he is looking for it.