It was noticed in the series of the three letters, particularly, that some observers were much more accurate in their work when the click was near one end of the series. In this experimental group, the comparison is between cases where the click is coördinated with (1) the first member of a visual series of five, (2) the middle member of a series of five, and (3) the last of such a series. The method was the same as that used in obtaining the results of Table IV. H was the letter used in each case for coördination. Results follow in Table V. TABLE V _Obs._ _H first_ _H middle_ _H last_ A Threshold Mean After Letter After Letter After Letter .010 (sec.) .021 (sec.) .025 (sec.) Range .072 (sec.) .085 (sec.) .093 (sec.) G Threshold Mean Before Letter On Letter Before Letter .007 (sec.) .007 (sec.) Range .124 (sec.) .083 (sec.) .151 (sec.) R Threshold Mean After Letter After Letter After Letter .032 (sec.) .016 (sec.) .042 (sec.) Range .464 (sec.) .398 (sec.) .369 (sec.) Sh Threshold Mean After Letter After Letter After Letter .025 (sec.) .015 (sec.) .030 (sec.) Range (sec.) .176 .176 .166 St Threshold Mean After Letter After Letter After Letter .050 (sec.) .062 (sec.) .078 (sec.) Range (sec.) .140 (sec.) .108 (sec.) .108 (sec.)