the Tropic of Cancer and gives distances between them as measured in three different ways the text first gives the distances between these stars by a unit called Mohnish oculto measured and weighed it is believed that this was an ingenious device that related the weight of escaping water to the passage of time it made possible the determination of distances between two stars in terms of time the second column of distances was in terms of degrees of the arc of the skies the full-day daylight and night time was