is still in its first stage, and that it will need a long cooeperation between science and industry in order to determine the desirable modifications and special conditions which may become necessary in making the employment of men partly dependent upon such psychological tests.  There can be no doubt that the experiments could be improved in many directions.  But even in this first, not adequately tested, form, an experimental investigation of this kind which demands from each individual hardly 10 minutes would be sufficient to exclude perhaps one fourth of those who are nowadays accepted into the service as motormen.  This 25 per cent of the applicants do not deserve any blame.  In many other occupations they might render excellent service; they are neither careless nor reckless, and they do not act against instructions, but their psychical mechanism makes them unfit for that particular combination of attention and imagination which ought to be demanded for the special task of the motorman.  If the many thousands of injury and the many hundreds of death cases could be reduced by such a test at least to a half, then the conditions of transportation would have been improved more than by any alterations in the technical apparatus, which usually are the only objects of interest in the discussion of specialists.  The whole world of industry will have to learn the great lesson, that of the three great factors, material, machine, and man, the man is not the least, but the most important.

IX

EXPERIMENTS IN THE INTEREST OF SHIP SERVICE

Where the avoidance of accidents is in question, the test of a special experimental method can seldom be made dependent upon a comparison with practical results, as we do not want to wait until the candidate has brought human life into danger.  The ordinary way of reaching the goal must therefore be an indirect one in such cases.  For the study of motormen the conditions are exceptionally favorable, as hundreds of thousands of accidents occur every year, but another practical example may be chosen from a field where it is, indeed, impossible to correlate the results with actual misfortunes, because the dangerous situations occur seldom; and nevertheless on account of their importance they demand most serious study.  I refer to the ship service, where the officer on the bridge may bring thousands into danger by one single slip of his mind.  I turn to this as a further concrete illustration in order to characterize at once the lengths to which such vocational studies may advance.