Another observation that has yet to be pointed out is the mathematical relationship between the different characteristic times and the retarder dosage. For t is , the relationship is approximately linear on a semi-logarithmic scale for etidronic acid (blue curve in Figure ). In contrast, sucrose and DL tartaric acid exhibit a small deviation from a linear relation, i.e., they show a non-exponential relationship between the onset time t is and the retarder dosage. Section 4.3 will discuss this in more detail.