A Psychological Invention.

Charles B. Bliss, a student in the graduate department of the Yale psychological laboratory, has perfected an invention which is of unusual importance, not only in delicate investigations on mental reaction, but of considerable practical value to electricians generally. While experimenting on the subject of the distraction, he devised a machine which solves the difficult problem of making or breaking two or more electrical currents at the same instant. Hitherto Ewald's key for recording the time of mental reaction has been used, but it will be replaced in laboratory and practical use by the Bliss Multiple Key, which not only saves one-half the labor in making experiments, but records variations of one-ten-thousandth of a second. It is made of unlacquered brass without platinum contact, and so arranged that five currents run through it. One, two or three of these can be made or broken at the same time, or broken for an instant and then made again, or these makes and breaks can be adjusted so as to occur one after the other, in any order. By reversing the key it gives three breaks and two makes.