It is in the nature of the case impossible to increase the wage incentive indefinitely. One large and scientifically managed plant has made remarkable provisions for staving off the time when the dead line is reached. They have taken stock account of the labor power they require, the amount of energy which each worker possesses, for the purpose of evaluation and payment. They have undertaken to cover as separate items each condition which affects a worker's relation to his job. They rate as separate items the worker's proficiency, reliability, continuity in service, indirect charges, increased cost of living, and periods of lay-off; they rate him according to the number of technical processes he is proficient in, whether or not he is engaged on more than one; they rate him if he attends the night school connected with the factory and shows in this way a disposition to learn other operations than, those he already knows. Why, they wonder, does only ten per cent of the force take advantage of the school and what, they are eager to find out, can they do further to secure the men's coöperation. For "coöperation," they say, "in a special way deserves credit, since it is unexpected ... certain well defined acts of coöperation will bring extra reward." Their rewards so carefully calculated did not seem to enlist response as spiritual in its nature as coöperation. It seemed that they had reached "the dead line" where wage stimulus fails to draw its hoped for response. To get from the workers the highest efficiency the scientifically managed plants pay for a task a stated rate based on piece or time; if the task is performed within the time set and the directions for doing the task as laid out by the management, are followed, the worker receives in addition to the regular rate, a bonus. Mr. H.L. Grant, while working with Mr. Taylor, discovered that there was weakness in the system of paying bonuses, and the weakness was not overcome until he devised a method of paying the workman for the time allowed plus a percentage of that time according to what he did. This method he declares constantly induced further effort and overcame what they discovered was the weakness in a flat bonus. As fair or as superior as this bonus may be in relation to the prevailing rate in the market, managers say that the workers are apt in time to fall below the standard as their work becomes routine, unless the incentive after a time is increased or changed in character. In other words the wage incentive is like a virus injection. The dose is not continuously effective, except as the amount is increased or altered. A usual method of keeping alive the financial incentive is profit sharing and schemes for participation in profits, but they are rewards of general merit and bids for continuity of service; they have no direct relation to the workers' efficiency and compliance with standards which distinguish the wage rewards of scientifically managed plants.