East of Sainte-Anne Market—now housed in its new wooden premises, fitted out in 1844 after the original market was converted into a parliament—stood a small two-storey brick building: the weigh house. This is where farmers and livestock raisers came to weigh their animals and harvests before selling them. The market clerk, keeper of the public scale, ensured the accuracy of the measurements. His weight measurements carried authority and built trust between sellers and buyers. At the time, two types of instruments were used: the beam balance, with its two pans, and the sliding-weight balance, where a weight moves along a graduated rod.

In another Montréal public market—the Bonsecours Market, built at the town’s eastern end—there was a large butter scale.

For small items, butchers and shopkeepers used two-pan countertop scales. The goods were placed in one pan, and weights in the other, until the balance levelled out.