_Apparent Exceptions to the Rule._--Exceptions to this rule which are rather apparent than real will occur to every one. The discovery of a great supply of mineral oil put an end to the use of whale oil for illuminating purposes, though it allowed the whale fishery to survive on a reduced scale and produce oil for other purposes, in so far as the rawest material, the whales themselves, were not exterminated. The exhaustion of a supply of raw material was here a dominant fact, and the effects it produced may be again expected when mineral oil shall, in turn, become scarce. Men will move out of the subgroup producing the crude oil, as nature forces them to do so, but their movement cannot be referred merely to improvement in the mode of extracting the oil or transporting and refining it. The fact which illustrates the rule we have stated is that while mineral oil drove whale oil out of the field as an illuminant, this did not reduce the number of men in the general group which produces illuminating oil. More men were set working in the oil fields than ceased working on the whaling ships. A new raw material was used in creating a similar finished product, and as the general industry which made this product grew larger rather than smaller, the total demand for labor in oil production was not lessened. This does not prove that old sailors did not suffer from the change. Young sailors could go to the oil fields or elsewhere, but men who were not adaptable could not do so, and the hardship thus entailed is not to be overlooked. We are, however, forming a judgment of movements which pervade a vast industrial system, and we need most to know what is their grand resultant. If that were a general displacement of labor, causing increasing idleness and suffering, the system that involved this result would stand condemned. The general resultant is the opposite of this. _A Drift of Labor toward Certain General Groups._--We have just noticed that movements of labor in the group system, caused by improvements in method, consist mainly in an upward flow of labor, accompanied by irregular lateral movements, the labor drifting to the right or the left as it is more strongly attracted now to one point and now to another on the same horizontal plane. The general mass of it swerves now to the right and now to the left in its general ascending course, though none may be actually expelled. This description of the drift of labor is too general even to describe all the permanent currents. Some entire groups produce only or chiefly luxurious goods, and to those there is the same drift of labor as there is to the upper subgroups of the general series. If there be a group of _D_'s making an article which only the well-to-do can afford to use, it will swell in size and in the volume of its output from the same causes--improved methods and general enrichment--which cause _A'''_, _B'''_, and _C'''_ to outgrow _A_, _B_, and _C_.