"We shall probably never secure the means of ascertaining the speed of nerve activities, because we lack the comparative distances from which the speed of a movement, in this respect analogous to light, could be calculated." We now know that sensory processes travel along the nerves on an average only about one hundred and ten feet per second, and often less than twenty-six feet. While you are performing the commonest judgment, electricity or light would have shot from continent to continent. The time-measurement of different mental processes is now one of the chief means which the psychologist uses for getting at mental laws. When certain measures are once determined, he uses these as the chemist does his familiar reagents, to dissolve the unfamiliar and more complicated combinations. The following table shows in decimals of a second about the average length of time which our commonest judgments occupy: SECONDS To recognize the direction of a ray of light .011 To recognize a color when one of two, as red and blue, .012 and expected to be seen To recognize the direction of ordinary sounds .015 To localize mentally, when blindfolded, any place on .021 our body, touched by another person Mentally to judge a distance when seen .022 To recognize the direction of loud sounds .062 To recognize capital letters .180 To recognize short English words .214 To recognize pictures of objects .163 To add single figures .170 Given a month, to name its season .164 to .354 To answer such questions as "Who wrote Hamlet?" .900 and over Such then, are a few out of the many problems which have been experimented upon in the Harvard Laboratory during the last year--problems in perception, association, attention, "reaction times," psycho-physic law, kinesthetics, esthetics, memory, will, and so on, covering nearly the whole range of mental phenomena. I have selected these few for presentation here, not for their importance over others, but because they could be simply described in these pages. The general aim of all the work is, however, very simple. As in the other sciences, it seeks to establish fact after fact, in orderly manner, along the whole line of mental nature; and by unifying these to work ever to a larger knowledge of the whole. [Illustration: WAX SPECIMENS IN THE MUSEUM.] FACILITIES FOR TEACHING.