How should containers (zharf) carrying the cargo be treated in the contract?
General Chapter
Al-Mughni
Book of Leasing
Primary text
If the containers are included in the weight measurement, their mention is not necessary. If they are not weighed, and they are of a known, unchanging type, such as sacks of wool or hair, the contract is valid without specifying them because they rarely vary significantly. However, if the containers vary, they must be specified by designation or description.
Supporting text
It is stated that if one hires an animal to carry three hundred ratl (pounds) of whatever one wishes, the contract is valid, but the hirer must not load it in a manner harmful to the animal, such as aggregating heavy materials like iron or mercury in one spot or placing them in a container that shifts violently, which tires the beast.