In the operation of these unsuccessful agreements the most serious stumbling blocks were the union "working rules," that is to say, the restrictive rules which unions strove to impose on employers in the exercise of their managerial powers in the shop, and for which the latter adopted the sinister collective designation of "restriction of output." Successful trade unionism has always pressed "working rules" on the employer. As early as the first decade of the nineteenth century, the trade societies then existing tried to impose on the masters the closed shop and restrictions on apprenticeship along with higher wages and shorter hours. As a union advances from an ephemeral association to a stable organization more and more the emphasis is shifted from wages to working rules. Unionists have discovered that on the whole wages are the unstable factor, going up or down, depending on fluctuating business conditions and cost of living; but that once they have established their power by making the employer accept their working rules, high wages will ultimately follow. These working rules are seldom improvisations of the moment, but, crude and one-sided as they often are, they are the product of a long labor experience and have taken many years to be shaped and hammered out. Since their purpose is protective, they can best be classified with reference to the particular thing in the workingman's life which they are designed to protect: the standard of living of the trade group, health, the security of the worker's job, equal treatment in the shop and an equal chance with other workmen in promotion, the bargaining power of the trade group, as a whole, and the safety of the union from the employer's attempts to undermine it. We shall mention only a few of these rules by way of illustration. Thus all rules relating to methods of wage payment, like the prohibition of piece work and of bonus systems (including those associated with scientific management systems), are primarily devices to protect the wage earner's rate of pay against being "nibbled away" by the employer; and in part also to protect his health against undue exertion. Other rules like the normal (usually the eight-hour) day with a higher rate for overtime; the rule demanding a guarantee of continuous employment for a stated time or a guarantee of minimum earnings, regardless of the quantity of work available in the shop; again the demand for the sharing of work in slack times among all employes; and further, when layoffs become necessary, the demand of recognition by the employer of a right to continuous employment based on "seniority" in the shop;--all these have for their common aim chiefly the protection of the job. Another sort of rules, like the obstruction to the splitting up of trades and the restrictions on apprenticeship, have in view the protection of the bargaining power of the craft group--through artificially maintaining an undiminished