The unit of mass was the libra (corresponding to 1 kg), defined as “the weight of distilled water contained in the cube of a mão travessa”.

Multiples of the libra:

• Arroba = 10 libras;
• Quintal = 100 libras;
• Tonelada = 1000 libras.

Submultiples of the libra:

• Décimo = 0,1 libra;
• Centésimo = 0,01 libra;
• Escrópulo = 0,001 libra;
• Decil = 0,0001 libra;
• Centil = 0,00001 libra.

In the display case we can see a set of standard weights consisting of:

• 2 arrobas;
• 1 arroba;
• 1/2 arroba;
• 1/4 arroba;
• 2 1/2 libra;
• 1/2 libra;
• 1/4 libra;