Professor Reed took a particular interest in this unusual cycle. To begin with, a 26-month cycle can't be explained by looking at the change of seasons on earth. Further, looking at the way in which the direction changes, one can see that the direction of the wind changes gradually from the upper layers to the lower layers of the stratosphere, so one is tempted to think the cause of the direction change originates somewhere outside the earth. However, no matter how hard you look, no planets or stars that move in some kind of 26 month cycle can be found. Reed searched through all manner of natural phenomenon for anything that had a 26 month cycle or time span. All he could come up with was the period of pregnancy of an elephant1).