 Heytesbury presents three different ways of “measuring” the speed of alteration in which the intensity of a quality varies form one point to another, or from instant to instant of time, or from point to point of the moving body: (1) by the degree (gradus) induced (a subject is considered to be altered faster when a higher degree is induced); (2) by the latitude of form acquired in comparison to the size of the subject (the speed of alteration is proportionally greater in a larger body); and (3) by the latitude acquired in a given time, regardless of the size of the subject undergoing alteration. Heytesbury holds the third position and claims that as in the case of local motion, the speed of alteration is to be measured at the point of the body where the rate of change is most rapid, that is, where the maximum latitude of form is acquired ([RSS] 1494: fol. 51ra).