In an explanation to his son, who mistakes his temperature as being measured in degrees Celsius rather than in degrees Fahrenheit, the father draws an analogy of the difference between the two as being as great as that between the metric system and the customary system measurements of kilometers and miles.
What Schatz does not understand is that the United States, England, and two of its old Imperial lands, Liberia and Mayanmar (formerly Burma), are the only ones that use the customary, or Imperial, system. Australia has some things yet measured by the customary system, such as pints of beer, but it converted to metric after 1966. Because Schatz has gone to school on the European continent, he has learned the metric system and Celsius. And, since a fever in Celsius is a temperature greater than 38 degrees Celsius (=100.4 degrees Fahrenheit), Schatz mistakenly believes he is dying when he hears that his temperature is "something like a hundred" when in reality his temperature is only a couple of degrees above normal, which is about 98.6 in Fahrenheit. Of course, the impact of this misunderstanding by Schatz, added to the fact that his father left his side and that the doctor later said his temperature was "one hundred and two," is devastating to the boy:
His hold over himself relaxed too, finally, and the next day it was very slack and he cried very easily at little things that were of no importance.
His courageous determination now shattered, the boy Schatz becomes detached and somewhat insecure in the end all because he doesn't understand the analogy likening the differences between the two temperature measurements (Celsius, Fahrenheit) to the differences between the two quantity measurements (metric, Imperial).